LDL triglycerides, hepatic lipase activity, and coronary artery disease: An epidemiologic and Mendelian randomization study

High-Density Lipoprotein Subfractions Remodeling: A Critical Process for the Treatment of Atherosclerotic Cardiovascular Diseases

Numerous studies have shown that a low level of high-density lipoprotein cholesterol (HDL-C) is an independent biomarker of cardiovascular disease. High-density lipoprotein (HDL) is considered to be a protective factor for atherosclerosis (AS). Therefore, raising HDL-C has been widely recognized as a promising strategy to treat atherosclerotic cardiovascular diseases (ASCVD). However, several studies have found that increasing HDL-C levels does not necessarily reduce the risk of ASCVD. HDL particles are highly heterogeneous in structure, composition, and biological function. Moreover, HDL particles from atherosclerotic patients exhibit impaired anti-atherogenic functions and these dysfunctional HDL particles might even promote ASCVD. This makes it uncertain that HDL-raising therapy will prevent and treat ASCVD. It is necessary to comprehensively analyze the structure and function of HDL subfractions. We review current advances related to HDL subfractions remodeling and highlight how current lipid-modifying drugs such as niacin, statins, fibrates, and cholesteryl ester transfer protein inhibitors regulate cholesterol concentration of HDL and specific HDL subfractions.

[Laboratory diagnostics of lipid metabolism disorders]

Clinically, disorders of lipid metabolism often remain without symptoms. Typical skin lesions, however, can be indicative. Secondary hyperlipoproteinemias (HLP) are more common than primary hyperlipoproteinemias; they can (partially) be improved by treating the underlying disease. Basic diagnostics consist of the determination of cholesterol, triglycerides, LDL cholesterol and HDL cholesterol. To exclude secondary HLP, glucose, HbA1C, TSH, transaminases, creatinine, urea, protein and protein in the urine are useful. Since virtually all routine methods for LDL-C are biased by high triglycerides, lipoprotein electrophoresis is indicated for triglycerides above 400 mg/dl (4.7 mmol/l). Primary HLPs have known or yet unknown genetic causes. Primary hyperlipidemias should be taken into consideration especially in young patients with an LDL cholesterol concentration are above 190 mg/dl (4.9 mmol/l) and/or triglycerides above 400 mg/dl (10 mmol/l) and secondary HLP (obesity, alcohol, diabetes mellitus, kidney disease) is excluded. The basic diagnostics is meaningfully extended by the measurement of lipoprotein (a) (Lp(a)). It is indicated in moderate and high risk of vascular disease, progression of atherosclerosis in "well-controlled" LDL cholesterol, familial clustering of atherosclerosis or high Lp(a), evidence for elevated Lp(a) coming from lipoprotein electrophoresis, aortic stenosis and in patients in whom statins have a poor effect. Genetic diagnostics needs to be considered if primary HLP is suspected. It is most frequently conducted for suspected familial hypercholesterolemia and has already been recommended in guidelines.

Prognostic significance of globulin/low-density lipoprotein ratio in patients with hepatocellular carcinoma after local ablative therapy: a retrospective cohort study

Background

Low-density lipoprotein (LDL) and globulin (GLOB) have been found to be predictors for some malignant tumors, but their predictive value in hepatocellular carcinoma (HCC) has hardly been elucidated. This study assessed the prognostic significance of GLOB to LDL ratio (GLR) in HCC patients before ablation.

Methods

This study analyzed 312 early-stage HCC patients who were hospitalized and underwent ablative treatment in Beijing You'an Hospital, Capital Medical University, from 1 January 2014 to 1 January 2019. The primary endpoint was the recurrence-free survival (RFS), calculated from treatment initiation to cancer recurrence, whereas the overall survival (OS) was measured from treatment initiation to death or last follow-up. Cox regression analysis was used to assess the GLR independently associated with recurrence and survival. OS and RFS were calculated by Kaplan-Meier analysis and compared between groups using the log rank test. The optimal cut-off value and prognostic role of GLR and other markers were evaluated via the receiver operating characteristic (ROC) curves and the Youden index.

Results

Univariate and multivariate analysis found that the tumor number, tumor size, and GLR were independent risk factors of relapse, whereas etiology, tumor number, tumor size, fibrinogen (Fib), and GLR were related to OS. We classified the patients into groups with high and low levels of GLR based on the optimal cut-off value of GLR identified by ROC curve. The cumulative 1-, 3-, and 5-year RFS rates in the low GLR group were 76.4%, 53.8%, and 43.4% respectively, whereas those in the high GLR group were 71%, 31%, and 22%, respectively (P<0.001). In terms of OS, the low GLR group showed a 1-, 3-, and 5-year OS of 99.5%, 92.0%, and 80.2% respectively, and 98%, 73%, and 63% respectively for the high GLR group (P<0.001). Finally, patients were stratified by GLR and tumor size. The outcomes revealed that patients in group A (GLR <16.54 and tumor size ≤30 mm) showed better prognosis than those in group B (GLR ≥16.54 and tumor size ≤30 mm or GLR <16.54 and tumor size >30 mm) and group C (GLR ≥16.54 and tumor size >30 mm) (P<0.001).

Conclusions

Preoperative GLR ratio has predictive value for patients with HCC who have undergone complete ablation.

Association of Multitrajectories of Lipid Indices With Premature Cardiovascular Disease: A Cohort Study

Background The multitrajectory model can identify joint longitudinal patterns of different lipids simultaneously, which might help better understand the heterogeneous risk of premature cardiovascular disease (CVD) and facilitate targeted prevention programs. This study aimed to investigate the associations between multitrajectories of lipids with premature CVD. Methods and Results The study enrolled 78 526 participants from the Kailuan study, a prospective cohort study in Tangshan, China. Five distinct multitrajectories of triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol over 6-year exposure were identified on the basis of Nagin's criteria, using group-based multitrajectory modeling. During a median follow-up of 6.75 years (507 645.94 person-years), 665 (0.85%) premature CVDs occurred. After adjustment for confounders, the highest risk of premature CVD was observed in group 4 (the highest and increasing triglyceride, optimal and decreasing LDL-C, low and decreasing high-density lipoprotein cholesterol) (hazard ratio [HR], 2.13 [95% CI, 1.36-3.32]), followed by group 5 (high and decreasing triglyceride, optimal and increasing LDL-C, low and decreasing high-density lipoprotein cholesterol) (HR, 2.07 [95% CI, 1.45-2.98]), and group 3 (optimal and increasing triglyceride, borderline high and increasing LDL-C, optimal and decreasing high-density lipoprotein cholesterol) (HR, 1.90 [95% CI, 1.32-2.73]). Conclusions Our results showed that the residual risk of premature CVD caused by increasing triglyceride levels remained high despite the fact that LDL-C levels were optimal or declining over time. These findings emphasized the importance of assessing the joint longitudinal patterns of lipids and undertaking potential interventions on triglyceride lowering to reduce the residual risk of premature CVD, even among individuals with optimal LDL-C levels.

Elevated LDL Triglycerides and Atherosclerotic Risk

BACKGROUND

It is unclear whether elevated low-density lipoprotein (LDL) triglycerides are associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD).

OBJECTIVES

This study tested the hypothesis that elevated LDL triglycerides are associated with an increased risk of ASCVD and of each ASCVD component individually.

METHODS

The study investigators used the Copenhagen General Population Study, which measured LDL triglycerides in 38,081 individuals with a direct automated assay (direct LDL triglycerides) and in another 30,208 individuals with nuclear magnetic resonance (NMR) spectroscopy (NMR LDL triglycerides). Meta-analyses aggregated the present findings with previously reported results.

RESULTS

During a median follow-up of 3.0 and 9.2 years, respectively, 872 and 5,766 individuals in the 2 cohorts received a diagnosis of ASCVD. Per 0.1 mmol/L (9 mg/dL) higher direct LDL triglycerides, HRs were 1.26 (95% CI: 1.17-1.35) for ASCVD, 1.27 (95% CI: 1.16-1.39) for ischemic heart disease, 1.28 (95% CI: 1.11-1.48) for myocardial infarction, 1.22 (95% CI: 1.08-1.38) for ischemic stroke, and 1.38 (95% CI: 1.21-1.58) for peripheral artery disease. Corresponding HRs for NMR LDL triglycerides were 1.26 (95% CI: 1.20-1.33), 1.33 (95% CI: 1.25-1.41), 1.41 (95% CI: 1.31-1.52), 1.13 (95% CI: 1.05-1.23), and 1.26 (95% CI: 1.10-1.43), respectively. The foregoing results were not entirely statistically explained by apolipoprotein B levels. In meta-analyses for the highest quartile vs the lowest quartile of LDL triglycerides, random-effects risk ratios were 1.50 (95% CI: 1.35-1.66) for ASCVD (4 studies; 71,526 individuals; 8,576 events), 1.62 (95% CI: 1.37-1.93) for ischemic heart disease (6 studies; 107,538 individuals; 9,734 events), 1.30 (95% CI: 1.13-1.49) for ischemic stroke (4 studies; 78,026 individuals; 4,273 events), and 1.53 (95% CI: 1.29-1.81) for peripheral artery disease (4 studies; 107,511 individuals; 1,848 events).

CONCLUSIONS

Elevated LDL triglycerides were robustly associated with an increased risk of ASCVD and of each ASCVD component individually in 2 prospective cohort studies and in meta-analyses of previous and present studies combined.

Bayesian network analysis of panomic biological big data identifies the importance of triglyceride-rich LDL in atherosclerosis development

Introduction

We sought to explore biomarkers of coronary atherosclerosis in an unbiased fashion.

Methods

We analyzed 665 patients (mean ± SD age, 56 ± 11 years; 47% male) from the GLOBAL clinical study (NCT01738828). Cases were defined by the presence of any discernable atherosclerotic plaque based on comprehensive cardiac computed tomography (CT). De novo Bayesian networks built out of 37,000 molecular measurements and 99 conventional biomarkers per patient examined the potential causality of specific biomarkers.

Results

Most highly ranked biomarkers by gradient boosting were interleukin-6, symmetric dimethylarginine, LDL-triglycerides [LDL-TG], apolipoprotein B48, palmitoleic acid, small dense LDL, alkaline phosphatase, and asymmetric dimethylarginine. In Bayesian analysis, LDL-TG was directly linked to atherosclerosis in over 95% of the ensembles. Genetic variants in the genomic region encoding hepatic lipase (LIPC) were associated with LIPC gene expression, LDL-TG levels and with atherosclerosis.

Discussion

Triglyceride-rich LDL particles, which can now be routinely measured with a direct homogenous assay, may play an important role in atherosclerosis development.

Clinical trial registration

GLOBAL clinical study (Genetic Loci and the Burden of Atherosclerotic Lesions); [https://clinicaltrials.gov/ct2/show/NCT01738828?term=NCT01738828&rank=1], identifier [NCT01738828].

Lipoprotein subfraction profiling in the search of new risk markers for myocardial infarction: The HUNT study

BACKGROUND

Traditional biomarkers used to measure risk of myocardial infarction (MI) only explain a modest proportion of the incidence. Lipoprotein subfractions have the potential to improve risk prediction of MI.

AIM

We aimed to identify lipoprotein subfractions that were associated with imminent MI risk.

METHODS

We identified apparently healthy participants with a predicted low 10-year risk of MI from The Trøndelag Health Survey 3 (HUNT3) that developed MI within 5 years after inclusion (cases, n = 50) and 100 matched controls. Lipoprotein subfractions were analyzed in serum by nuclear magnetic resonance spectroscopy at time of inclusion in HUNT3. Lipoprotein subfractions were compared between cases and controls in the full population (N = 150), and in subgroups of males (n = 90) and females (n = 60). In addition, a sub analysis was performed in participants that experienced MI within two years and their matched controls (n = 56).

RESULTS

None of the lipoprotein subfractions were significantly associated with future MI when adjusting for multiple testing (p<0.002). At nominal significance level (p<0.05), the concentration of apolipoprotein A1 in the smallest high-density lipoprotein (HDL) subfractions was higher in cases compared to controls. Further, in sub analyses based on sex, male cases had lower lipid concentration within the large HDL subfractions and higher lipid concentration within the small HDL subfractions compared to male controls (p<0.05). No differences were found in lipoprotein subfractions between female cases and controls. In sub analysis of individuals suffering from MI within two years, triglycerides in low-density lipoprotein were higher among cases (p<0.05).

CONCLUSION

None of the investigated lipoprotein subfractions were associated with future MI after adjustment for multiple testing. However, our findings suggests that HDL subfractions may be of interest in relation to risk prediction for MI, especially in males. This need to be further investigated in future studies.

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.

LDL retention time in plasma can be -based on causation- estimated by the lipid composition of LDL and other lipoproteins

Introduction

Information on LDL’s dynamic behaviour of LDL (i.e. production rate and fractional catabolic rate) are of interest if pathologies, lipid-lowering strategies or LDL-metabolism itself are investigated. Determination of these rates is costly and elaborate. Here we studied the interrelationship of LDL mass, its composition and other lipoproteins. Based on this data, we deducted information about LDL’s dynamic behaviour.

Methods

Lipoprotein profiles of n = 236 participants are evaluated. Plasma was separated by sequential ultracentrifugation into VLDL, IDL, LDL and HDL. Additionally, LDL and HDL were separated into subfractions. Stepwise multiple linear regressions were used to study LDL’s ApoB mass and lipid composition. Relying on these results and on causation, we constructed a mathematical model to estimate LDL’s retention time.

Results

The ApoB mass in LDL correlated best among all measured parameters (including corresponding lipid compositions but using no LDL-associated parameters) with the cholesterol ester content in IDL. TG/CE ratios in LDL’s subfractions were strongly correlated with the corresponding ratios in IDL and HDL. The constructed mathematical model links the TG/CE ratio of LDL and HDL to LDL’s ApoB concentration and enables a good estimate of LDL’s retention time in plasma.

Discussion

Relying on our statistic evaluations, we assume that i) the production of nascent LDL via IDL as well as ii) LDL’s prolonged retention are mapped by the TG/CE ratio in LDL subfractions. HDL’s TG/CE ratio is associated with the change in LDL’s TG/CE ratio during its retention in plasma. Our mathematical model uses this information and enables–by relying on causation- a good estimation of LDL’s retention time.

Polyvascular disease, pulse pressure and mortality

Background: Peripheral arterial disease (PAD), coronary artery disease (CAD) and carotid stenosis (CS) are robust predictors of mortality. The value of individual vascular beds in polyvascular disease (PVD) to predict mortality in patients with atherosclerotic burden is not clear. Therefore, we have examined the predictive value of PAD, CAD and CS in patients at intermediate to high risk of cardiovascular (CV) disease. Patients and methods: In our retrospective observational study we analyzed baseline data from the Ludwigshafen Risk and Cardiovascular Health (LURIC) study, a monocentric cohort study of 3316 patients referred to coronary angiography. Results: As the number of atherosclerotic vascular beds increased, the hazard ratios (HRs) for both all-cause mortality and CV mortality significantly increased in a multivariate analysis after adjusting for age, sex, body mass index, diabetes mellitus and estimated glomerular filtration rate, with HRs of 1.36 (95%CI: 1.11-1.68), 2.56 (95%CI: 2.01-3.26), 2.84 (95%CI: 1.93-4.17) and 1.56 (95%CI: 1.19-2.06), 2.70 (95%CI: 1.97-3.72), 3.50 (95%CI: 2.19-5.62), respectively. The combination of PAD with either CAD or CS was associated with higher HRs for all-cause (HR 2.81 and 7.53, respectively) and CV (HRs 2.80 and 6.03, respectively) mortality compared with the combination of CAD and CS (HRs 1.94 and 2.43, respectively). The presence of PVD was associated with higher age, systolic blood pressure, pulse pressure (PP; a marker of vascular stiffness), former smoking and inversely with lower eGFR. Conclusions: We show that as the number of atherosclerotic vascular beds increases, all-cause and CV mortality rates increase in parallel. Simultaneous prevalence of PAD is associated with significantly higher all-cause and CV mortality rates compared with CS coexistence. Furthermore, increasing atherosclerotic load may contribute to vascular stiffness and impaired renal function.

The LDL Apolipoprotein B-to-LDL Cholesterol Ratio: Association with Cardiovascular Mortality and a Biomarker of Small, Dense LDLs

Background and Objective: Small, dense low-density lipoproteins (LDLs) are considered more atherogenic than normal size LDLs. However, the measurement of small, dense LDLs requires sophisticated laboratory methods, such as ultracentrifugation, gradient gel electrophoresis, or nuclear magnetic resonance. We aimed to analyze whether the LDL apolipoprotein B (LDLapoB)-to-LDL cholesterol (LDLC) ratio is associated with cardiovascular mortality and whether this ratio represents a biomarker for small, dense LDLs. Methods: LDLC and LDLapoB were measured (beta-quantification) and calculated (according to Friedewald and Baca, respectively) for 3291 participants of the LURIC Study, with a median (inter-quartile range) follow-up for cardiovascular mortality of 9.9 (8.7−10.7) years. An independent replication cohort included 1660 participants. Associations of the LDLapoB/LDLC ratio with LDL subclass particle concentrations (ultracentrifugation) were tested for 282 participants. Results: In the LURIC Study, the mean (standard deviation) LDLC and LDLapoB concentrations were 117 (34) and 85 (22) mg/dL, respectively; 621 cardiovascular deaths occurred. Elevated LDLapoB/LDLC (calculated and measured) ratios were significantly and independently associated with increased cardiovascular mortality in the entire cohort (fourth vs. first quartile: hazard ratio (95% confidence interval) = 2.07 (1.53−2.79)) and in statin-naïve patients. The association between calculated LDLapoB/LDLC ratio and cardiovascular mortality was replicated in an independent cohort. High LDLapoB/LDLC ratios were associated with higher LDL5 and LDL6 concentrations (both p < 0.001), but not with concentrations of larger LDLs. Conclusions: Elevated measured and calculated LDLapoB/LDLC ratios are associated with increased cardiovascular mortality. Use of LDLapoB/LDLC ratios allows estimation of the atherogenic risk conferred by small, dense LDLs.

Metabolic Properties of Lowdensity Lipoprotein (LDL) Triglycerides in Patients with Type 2 Diabetes, Comparison with Small Dense LDL-Cholesterol

AIMS

Abnormal compositional changes in low-density lipoprotein (LDL) particles, such as triglyceride (TG) enrichment and size reduction, are common in patients with diabetes. Several cohort studies have demonstrated that LDL-TG and sdLDL-cholesterol (C) are sensitive biomarkers for predicting atherosclerotic cardiovascular diseases beyond LDL-C. Although sdLDL has been extensively studied, little is known about the properties of LDL-TG. We investigated similarities or differences between LDL-TG and sdLDL-C.

METHODS

Fasting plasma was obtained from 1,085 patients with type 2 diabetes who were enrolled in the diabetes regional cohort study (ViNA Cohort). LDL-TG and sdLDL-C concentrations were measured using a homogeneous assay established by us. In a subset of subjects, LDL-TG and sdLDL-C levels were measured postprandially or after treatment with lipid-lowering drugs.

RESULTS

In a quartile analysis, higher LDL-TG quartiles were associated with higher frequency of female and fibrate users, whereas sdLDL-C quartiles were associated with frequency of men, drinking, and metabolic syndrome-related measurements. Higher quartiles of LDL-TG/LDL-C were associated with smoking, drinking, fibrate users, and statin users. LDL-TG was significantly correlated with TG, LDL-C, sdLDL-C, and apolipoprotein (apo) B, with apoB being the primary determinant. LDL-TG correlated to high sensitive C-reactive protein (CRP) independently of other lipids. Mean LDL-TG did not change with fasting/non-fasting. Statin treatment reduced LDL-TG, whereas fibrates increased it, but these drugs reduced sdLDL-C equally.

CONCLUSIONS

LDL-TG levels were more tightly regulated by the number of LDL particles than plasma TG levels were. SdLDL-C was closely associated with metabolic syndrome-related factors, whereas LDL-TG was associated with low-grade systemic inflammation.

RNA-based therapy in the management of lipid disorders: a review

This review focuses on antisense oligonucleotides and small interfering ribonucleic acid therapies approved or under development for the management of lipid disorders. Recent advances in RNA-based therapeutics allow tissue-specific targeting improving safety. Multiple potential target proteins have been identified and RNA-based therapeutics have the potential to significantly improve outcomes for patients with or at risk for atherosclerotic cardiovascular disease. The advantages of RNA-based lipid modifying therapies include the ability to reduce the concentration of almost any target protein highly selectively, allowing for more precise control of metabolic pathways than can often be achieved with small molecule-based drugs. RNA-based lipid modifying therapies also make it possible to reduce the expression of target proteins for which there are no small molecule inhibitors. RNA-based therapies can also reduce pill burden as their administration schedule typically varies from weekly to twice yearly injections. The safety profile of most current RNA-based lipid therapies is acceptable but adverse events associated with various therapies targeting lipid pathways have included injection site reactions, inflammatory reactions, hepatic steatosis and thrombocytopenia. While the body of evidence for these therapies is expanding, clinical experience with these therapies is currently limited in duration and the results of long-term studies are eagerly awaited.

Process analysis of anthracycline adverse reactions in breast cancer patients with postoperative chemotherapy

This study aimed to explore the clinical adverse effects of anthracyclines on patients undergoing chemotherapy after breast cancer surgery. A total of 118 patients who received anthracycline chemotherapy after breast cancer surgery were selected as the research object, and the changes of echocardiogram, ECG, myocardial enzymes and blood biochemical indices before, during and after chemotherapy were studied. SPSS V.20 was used to conduct statistical analysis. The differences in heart rate, ST-segment abnormalities, creatine kinase, lactate dehydrogenase, hemoglobin, albumin, triglycerides and high-density lipoprotein were statistically significant. Heart rate and triglycerides increased significantly in the early stage of chemotherapy; ST-segment abnormality increased during the entire chemotherapy period; creatine kinase and lactate dehydrogenase increased significantly in the late stage of chemotherapy; hemoglobin and albumin decreased in the early stage of chemotherapy. The magnitude is large; high-density lipoprotein decreases throughout the chemotherapy period. In anthracycline chemotherapy regimens, bone marrow suppression and dyslipidemia occur in the early stage of chemotherapy, and the risk of cardiotoxicity is higher in the late stage of chemotherapy.

Triglyceride-rich lipoproteins, apolipoprotein C-III, angiopoietin-like protein 3, and cardiovascular events in older adults: Atherosclerosis Risk in Communities (ARIC) study

AIMS

Despite statin and antihypertensive therapies, older Americans have high atherosclerotic cardiovascular disease (ASCVD) risk. Novel measures of triglyceride-rich lipoproteins, low-density lipoprotein triglycerides (LDL-TG), and remnant-like particle cholesterol (RLP-C), are associated with ASCVD in middle-aged adults. Polymorphisms in genes encoding angiopoietin-related protein 3 (ANGPTL3) and apolipoprotein C-III (apoC-III), two proteins involved in triglyceride catabolism, are associated with increased risk for hypertriglyceridaemia and ASCVD and are potential therapeutic targets. We examined associations of LDL-TG, RLP-C, apoC-III, and ANGPTL3 levels with ASCVD events in older adults in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS AND RESULTS

In 6359 participants (mean age 75.8 ± 5.3 years) followed for ASCVD events [coronary heart disease (CHD) or ischaemic stroke] up to 6 years, associations between LDL-TG, RLP-C, apoC-III, and ANGPTL3 and ASCVD events were assessed using Cox regression. With adjustment for age, sex, and race, RLP-C, LDL-TG, apoC-III, and ANGPTL3 (as continuous variables) were significantly associated with CHD. However, after adjustment for traditional risk factors and lipid-lowering medications, only LDL-TG and ANGPTL3 were significantly associated with ASCVD events [hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.25-2.37 per log unit increase in LDL-TG; HR 1.63, 95% CI 1.17-2.28 per log unit increase in ANGPTL3].

CONCLUSIONS

In older adults, LDL-TG, RLP-C, apoC-III, and ANGPTL3 were associated with CHD events in minimally adjusted models; LDL-TG and ANGPTL3 remained independent predictors of ASCVD events with further adjustment. Future studies should assess potential benefit of lowering hepatic apoC-III or ANGPTL3 expression in patients with elevated triglyceride-rich lipoproteins.

Effects of Alirocumab on Triglyceride Metabolism: A Fat-Tolerance Test and Nuclear Magnetic Resonance Spectroscopy Study

Background: PCSK9 antibodies strongly reduce LDL cholesterol. The effects of PCSK9 antibodies on triglyceride metabolism are less pronounced. The present study aimed to investigate in detail the effects of alirocumab on triglycerides, triglyceride-rich lipoproteins, and lipase regulators. Methods: A total of 24 patients with an indication for treatment with PCSK9 antibodies were recruited. There were two visits at the study site: the first before initiation of treatment with alirocumab and the second after 10 weeks of treatment. Fat-tolerance tests, nuclear magnetic resonance spectroscopy, and enzyme-linked immunosorbent assays were performed to analyze lipid metabolism. Results: A total of 21 participants underwent the first and second investigation. Among these, two participants only received alirocumab twice and 19 patients completed the trial per protocol. All of them had atherosclerotic vascular disease. There was no significant effect of alirocumab treatment on fasting triglycerides, post-prandial triglycerides, or lipoprotein-lipase regulating proteins. Total, large, and small LDL particle concentrations decreased, while the HDL particle concentration increased (all p < 0.001). Mean total circulating PCSK9 markedly increased in response to alirocumab treatment (p < 0.001). Whereas PCSK9 increased more than three-fold in all 19 compliant patients, it remained unchanged in those two patients with two injections only. Conclusion: Significant effects of alirocumab on triglyceride metabolism were not detectable in the ALIROCKS trial. The total circulating PCSK9 concentration might be a useful biomarker to differentiate non-adherence from non-response to PCSK9 antibodies.

The effect of non-invasively obtained central blood pressure on cardiovascular outcome in diabetic patients in Assiut University Hospitals

Background

The major cause of morbidity and mortality in diabetes is cardiovascular disease, which is exacerbated by the presence of hypertension. Therefore, proper control of BP in diabetic hypertensive patients is essential. Few studies have specifically investigated the prognostic significance of central BP in Egyptian populations with diabetes and hypertension and its relation with cardiovascular outcome. This study aims to evaluate relation between central BP and diabetic composite cardiovascular complications.

Results

Diabetic patients with CVD were significantly older (p value < 0.01), obese (p value < 0.01) with long duration of diabetes (p value < 0.001) and had significantly higher peripheral and central systolic and diastolic BP and higher AIx@75(p values < 0.01) than those without CVD. Regarding the metabolic parameters, they had significantly higher fasting blood glucose, HbA1c, and higher blood cholesterol levels (p values < 0.001), higher LDL (p value < 0.01), triglycerides levels (p value = 0.014), and microalbuminuria (p value = 0.028). Logistic regression analysis found increased BMI, central systolic BP, and AIx@75 were independent predictors of composite CVD (p values < 0.05).

Conclusions

There is a pattern of favorability towards central rather than peripheral BP indices to predict the occurrence of CVD in diabetic patients.

Deficiency of ASGR1 in pigs recapitulates reduced risk factor for cardiovascular disease in humans

Genetic variants in the asialoglycoprotein receptor 1 (ASGR1) are associated with a reduced risk of cardiovascular disease (CVD) in humans. However, the underlying molecular mechanism remains elusive. Given the cardiovascular similarities between pigs and humans, we generated ASGR1-deficient pigs using the CRISPR/Cas9 system. These pigs show age-dependent low levels of non-HDL-C under standard diet. When received an atherogenic diet for 6 months, ASGR1-deficient pigs show lower levels of non-HDL-C and less atherosclerotic lesions than that of controls. Furthermore, by analysis of hepatic transcriptome and in vivo cholesterol metabolism, we show that ASGR1 deficiency reduces hepatic de novo cholesterol synthesis by downregulating 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and increases cholesterol clearance by upregulating the hepatic low-density lipoprotein receptor (LDLR), which together contribute to the low levels of non-HDL-C. Despite the cardioprotective effect, we unexpectedly observed mild to moderate hepatic injury in ASGR1-deficient pigs, which has not been documented in humans with ASGR1 variants. Thus, targeting ASGR1 might be an effective strategy to reduce hypercholesterolemia and atherosclerosis, whereas further clinical evidence is required to assess its hepatic impact.

Previous studies have reported an association between ASGR1 variants and CVD in humans. However, the underlying mechanism is unknown. We used ASGR1-deficient pig to recapitulate the reduced risk features of CVD in humans with ASGR1 variants, indicating that ASGR1 inhibition could be an effective strategy to treat atherosclerotic CVD. Our results highlight the demand for taking advantage of genetically modified large animal models to investigate the pathogenesis and therapeutic development of CVD in humans. Unexpectedly, we demonstrate the first link between ASGR1 deficiency and liver injury, a feature that has not been documented in humans with ASGR1 variants. These results suggest that ASGR1 might be an effective target for reducing CVD, whereas revealing a genetic predisposition to liver disease in humans with ASGR1 variants.

Microtubule affinity regulating kinase 4: A promising target in the pathogenesis of atherosclerosis

Microtubule affinity regulating kinase 4 (MARK4), an important member of the serine/threonine kinase family, regulates the phosphorylation of microtubule-associated proteins and thus modulates microtubule dynamics. In human atherosclerotic lesions, the expression of MARK4 is significantly increased. Recently, accumulating evidence suggests that MARK4 exerts a proatherogenic effect via regulation of lipid metabolism (cholesterol, fatty acid, and triglyceride), inflammation, cell cycle progression and proliferation, insulin signaling, and glucose homeostasis, white adipocyte browning, and oxidative stress. In this review, we summarize the latest findings regarding the role of MARK4 in the pathogenesis of atherosclerosis to provide a rationale for future investigation and therapeutic intervention.

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.

Subclass distribution of low-density lipoprotein triglyceride and the clustering of metabolic syndrome components in Japanese children

BACKGROUND

Recent studies demonstrated that low-density lipoprotein-tryglyceride (LDL-TG) may represent another marker of cardiovascular risks. We therefore measured LDL-TG including the low-density lipoprotein (LDL) subclass distribution and investigated the association between LDL-TG subclass profile and the clustering of metabolic syndrome (MetS) components and insulin resistance in Japanese children.

METHODS

The study included 237 schoolchildren (boys 115, girls 122). Four subclasses of low-density lipoprotein-tryglyceride (large, medium, small, and very small) was quantified using high-performance liquid chromatography. Total LDL-TG and TG levels in LDL subclasses were evaluated among four MetS component groups; non-abdominal obesity, abdominal obesity, pre-MetS, and MetS.

RESULTS

Total LDL-TG (P = 0.0003, P = 0.0175) and triglyceride levels in LDL subclasses were significantly different among four MetS component groups (large: P = 0.0002, P = 0.0084; medium: P = 0.0009, P = 0.0491; small: P =0.0025, P = 0.0509; very small: P = 0.0808, P = 0.0228; boys and girls, respectively). Total LDL-TG (r = 0.411, P < 0.0001, r = 0.378. P < 0.0001) and triglyceride levels in LDL subclasses correlated positively with the homeostasis model of assessment ratio (large: r = 0.396, P < 0.0001, r = 0.346, P < 0.0001; medium: r = 0.274, P = 0.0030, r = 0.228, P = 0.0115; small: r = 0.342, P = 0.0002, r = 0.292, P = 0.0011; very small: r = 0.385, P < 0.0001, r = 0.426, P < 0.0001, boys and girls, respectively).

CONCLUSIONS

Subclass distribution of LDL-TG was significantly associated with the clustering of MetS components in both sexes, and insulin resistance is a significant determinant of LDL-TG in all LDL subclasses. Lipoprotein-tryglyceride subclass analysis, rather than LDL-C, may provide a precise evaluation for cardiovascular disease risks in children with MetS.

Functional Haplotype of LIPC Induces Triglyceride-Mediated Suppression of HDL-C Levels According to Genome-Wide Association Studies

Hepatic lipase (encoded by LIPC) is a glycoprotein in the triacylglycerol lipase family and mainly synthesized in and secreted from the liver. Previous studies demonstrated that hepatic lipase is crucial for reverse cholesterol transport and modulating metabolism and the plasma levels of several lipoproteins. This study was conducted to investigate the suppression effect of high-density lipoprotein cholesterol (HDL-C) levels in a genome-wide association study and explore the possible mechanisms linking triglyceride (TG) to LIPC variants and HDL-C. Genome-wide association data for TG and HDL-C were available for 4657 Taiwan-biobank participants. The prevalence of haplotypes in the LIPC promoter region and their effects were calculated. The cloned constructs of the haplotypes were expressed transiently in HepG2 cells and evaluated in a luciferase reporter assay. Genome-wide association analysis revealed that HDL-C was significantly associated with variations in LIPC after adjusting for TG. Three haplotypes (H1: TCG, H2: CTA and H3: CCA) in LIPC were identified. H2: CTA was significantly associated with HDL-C levels and H1: TCG suppressed HDL-C levels when a third factor, TG, was included in mediation analysis. The luciferase reporter assay further showed that the H2: CTA haplotype significantly inhibited luciferase activity compared with the H1: TCG haplotype. In conclusion, we identified a suppressive role for TG in the genome-wide association between LIPC and HDL-C. A functional haplotype of hepatic lipase may reduce HDL-C levels and is suppressed by TG.

Residual Cardiovascular Risk at Low LDL: Remnants, Lipoprotein(a), and Inflammation

BACKGROUND

Current guidelines target low-density lipoprotein cholesterol (LDL-C) concentrations to reduce atherosclerotic cardiovascular disease (ASCVD) risk, and yet clinical trials demonstrate persistent residual ASCVD risk despite aggressive LDL-C lowering.

CONTENT

Non-LDL-C lipid parameters, most notably triglycerides, triglyceride-rich lipoproteins (TGRLs), and lipoprotein(a), and C-reactive protein as a measure of inflammation are increasingly recognized as associated with residual risk after LDL-C lowering. Eicosapentaenoic acid in statin-treated patients with high triglycerides reduced both triglycerides and ASCVD events. Reducing TGRLs is believed to have beneficial effects on inflammation and atherosclerosis. High lipoprotein(a) concentrations increase ASCVD risk even in individuals with LDL-C < 70 mg/dL. Although statins do not generally lower lipoprotein(a), proprotein convertase subtilisin/kexin type 9 inhibitors reduce lipoprotein(a) and cardiovascular outcomes, and newer approaches are in development. Persistent increases in C-reactive protein after intensive lipid therapy have been consistently associated with increased risk for ASCVD events.

SUMMARY

We review the evidence that biochemical assays to measure TGRLs, lipoprotein(a), and C-reactive protein are associated with residual risk in patients treated to low concentrations of LDL-C. Growing evidence supports a causal role for TGRLs, lipoprotein(a), and inflammation in ASCVD; novel therapies that target TGRLs, lipoprotein(a), and inflammation are in development to reduce residual ASCVD risk.

Long-term prognostic utility of low-density lipoprotein (LDL) triglyceride in real-world patients with coronary artery disease and diabetes or prediabetes

BACKGROUND

Recent guidelines highlighted the association between atherosclerosis and triglyceride-enriched lipoproteins in patients with impaired glucose metabolism. However, evidence from prospective studies for long-term prognostic utility of low-density lipoprotein triglyceride (LDL-TG) in real-world patients with prediabetes (Pre-DM) or diabetes mellitus (DM) and coronary artery disease (CAD) is currently not available. The aim of the present study was to evaluate the impact of LDL-TG on major adverse cardiovascular events (MACEs) in patients with stable CAD under different glucose metabolism status.

METHODS

A total of 4381 patients with CAD were consecutively enrolled and plasma LDL-TG level was measured by an automated homogeneous assay. They were categorized according to both status of glucose metabolism [DM, Pre-DM, normal glycaemia regulation (NGR)] and tertiles of LDL-TG. All subjects were followed up for the occurrence of MACEs.

RESULTS

During a median of 5.1 (interquartile range 3.9 to 5.9) years' follow-up, 507 (11.6%) MACEs occurred. Cubic spline models showed a significant association between LDL-TG and MACEs in DM and Pre-DM but not in NGR. When the combined effect of elevated LDL-TG and glucose disorders was considered for risk stratification, the medium tertile of LDL-TG plus DM, and the highest tertile of LDL-TG plus Pre-DM or plus DM subgroups were associated with significantly higher risk of MACEs after adjustment of confounders including triglyceride [hazard ratios (95% confidence intervals): 1.843 (1.149-2.955), 1.828 (1.165-2.867), 2.212 (1.396-3.507), all p < 0.05]. Moreover, adding LDL-TG into the original model increased the C-statistic from 0.687 to 0.704 (∆C-statistic = 0.016, p = 0.028) and from 0.734 to 0.749 (∆C-statistic = 0.014, p = 0.002) in Pre-DM and DM, respectively.

CONCLUSIONS

In this longitudinal cohort study on real-world practice, higher LDL-TG was associated with worse outcomes among Pre-DM and DM patients with stable CAD.

Maternal High-Sucrose Diet Affects Phenotype Outcome in Adult Male Offspring: Role of Zbtb16

Overnutrition in pregnancy and lactation affects fetal and early postnatal development, which can result in metabolic disorders in adulthood. We tested a hypothesis that variation of the Zbtb16 gene, a significant energy metabolism regulator, modulates the effect of maternal high-sucrose diet (HSD) on metabolic and transcriptomic profiles of the offspring. We used the spontaneously hypertensive rat (SHR) strain and a minimal congenic rat strain SHR-Zbtb16, carrying the Zbtb16 gene allele originating from the PD/Cub rat, a metabolic syndrome model. Sixteen-week-old SHR and SHR-Zbtb16 rat dams were fed either standard diet (control groups) or a high-sucrose diet (HSD, 70% calories as sucrose) during pregnancy and 4 weeks of lactation. In dams of both strains, we observed an HSD-induced increase of cholesterol and triacylglycerol concentrations in VLDL particles and a decrease of cholesterol and triacylglycerols content in medium to very small LDL particles. In male offspring, exposure to maternal HSD substantially increased brown fat weight in both strains, decreased triglycerides in LDL particles, and impaired glucose tolerance exclusively in SHR. The transcriptome assessment revealed networks of transcripts reflecting the shifts induced by maternal HSD with major nodes including mir-126, Hsd11b1 in the brown adipose tissue, Pcsk9, Nr0b2 in the liver and Hsd11b1, Slc2a4 in white adipose tissue. In summary, maternal HSD feeding during pregnancy and lactation affected brown fat deposition and lipid metabolism in adult male offspring and induced major transcriptome shifts in liver, white, and brown adipose tissues. The Zbtb16 variation present in the SHR-Zbtb16 led to several strain-specific effects of the maternal HSD, particularly the transcriptomic profile shifts of the adult male offspring.

Association of Dietary Phytosterols with Cardiovascular Disease Biomarkers in Humans

Cardiovascular disease (CVD) is a leading cause of death worldwide. Elevated concentrations of serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) are major lipid biomarkers that contribute to the risk of CVD. Phytosterols well known for their cholesterol-lowering ability, are non-nutritive compounds that are naturally found in plant-based foods and can be classified into plant sterols and plant stanols. Numerous clinical trials demonstrated that 2 g phytosterols per day have LDL-C lowering efficacy ranges of 8-10%. Some observational studies also showed an inverse association between phytosterols and LDL-C reduction. Beyond the cholesterol-lowering beneficial effects of phytosterols, the association of phytosterols with CVD risk events such as coronary artery disease and premature atherosclerosis in sitosterolemia patients have also been reported. Furthermore, there is an increasing demand to determine the association of circulating phytosterols with vascular health biomarkers such as arterial stiffness biomarkers. Therefore, this review aims to examine the ability of phytosterols for CVD risk prevention by reviewing the current data that looks at the association between dietary phytosterols intake and serum lipid biomarkers, and the impact of circulating phytosterols level on vascular health biomarkers. The clinical studies in which the impact of phytosterols on vascular function is investigated show minor but beneficial phytosterols effects over vascular health. The aforementioned vascular health biomarkers are pulse wave velocity, augmentation index, and arterial blood pressure. The current review will serve to begin to address the research gap that exists between the association of dietary phytosterols with CVD risk biomarkers.

Triglycerides and ASCVD Risk Reduction: Recent Insights and Future Directions

PURPOSE OF REVIEW

This review focuses on recent evidence examining the role triglycerides (TG) and triglyceride-enriched lipoproteins (TGRL) play in atherosclerotic cardiovascular disease (ASCVD). It also provides a succinct overview of current and future TG-lowering therapies for ASCVD risk reduction.

RECENT FINDINGS

Epidemiological and Mendelian randomization studies have consistently shown that TGRL are strongly associated with ASCVD. REDUCE-IT demonstrated cardiovascular benefit with icosapent ethyl in high-risk patients with hypertriglyceridemia on statin therapy. Polymorphisms in APOC3 and ANGPTL3 are associated with ASCVD and use of RNA-interfering therapies to target these proteins has shown TG lowering in early phase trials. TG and TGRL are causally associated with ASCVD. Lifestyle modifications and statin therapy can lower TG/TGRL and are considered first-line treatment for hypertriglyceridemia. Icosapent ethyl has been shown to reduce residual ASCVD risk in high-risk patients on maximally tolerated statins. Ongoing clinical trials will better define optimal therapy for patients on statins with residual hypertriglyceridemia.

Association of changes in lipids with risk of myocardial infarction among people without lipid-lowering therapy

BACKGROUND AND AIMS

Although serum lipids are widely accepted as independent predictors of myocardial infarction (MI), there is insufficient evidence for associations of changes in lipid levels with MI. The present study aimed at investigating the associations between changes in lipids and incidence of MI in people without lipid-lowering therapy.

METHODS

64,031 Chinese participants (mean age: 53.42 ± 11.95 years) without previous MI were enrolled in the study. The participants were divided into four categories based on quartiles of lipid changes. Multivariable Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for MI.

RESULTS

During a median follow-up of 7.03 years, 599 individuals developed MI. After adjustment for covariates, increased total cholesterol (TC), increased low-density lipoprotein cholesterol (LDL-C), increased non-high-density lipoprotein cholesterol (non-HDL-C), and decreased high-density lipoprotein cholesterol (HDL-C) were associated with elevated risk of MI, with HRs (95% CIs) in the highest quartile group compared with the lowest quartile group of 1.56 (1.21-2.01), 1.96 (1.49-2.57), 1.95 (1.52-2.50), and 0.69 (0.53-0.90), respectively. However, changes in triglyceride (TG) were not associated with MI risk (p = 0.8030).

CONCLUSIONS

Changes in levels of TC, LDL-C, non-HDL-C, and HDL-C, but not TG, were associated with risk of MI. Early detection and control of lipid levels may be beneficial and necessary for young people and those with healthy lipid levels at baseline.

[Inborn errors of high-density lipoprotein metabolism]

Both low and very high levels of high-density lipoprotein cholesterol (HDL-C) increase the risk of atherosclerotic cardiovascular disease (ASCVD) and shorten life expectancy. Low and high levels of HDL‑C are often caused by underlying diseases, lifestyle or medication, which should primarily be excluded. Much less frequently, monogenic diseases due to mutations in the APOA1, ABCA1 and LCAT genes are the cause of very low or unmeasurable HDL‑C levels or in the CETP, LIPC and SCARB1 genes for very high HDL‑C values. Genetic and detailed biochemical diagnostics should be considered, especially in cases of absolute HDL deficiency, early onset ASCVD or the presence of clinical symptoms or laboratory values characteristic for deficiencies of apolipoprotein A‑I (ApoA-I), lecithin cholesterol acyltransferase (LCAT) or Tangier disease. These included corneal opacities, xanthomas, large tonsils, hepatomegaly, peripheral neuropathy, proteinuria, anemia or thrombocytopenia. Sequencing of the APOA1 gene should also be considered in familial amyloidosis. There is no specific treatment for monogenic HDL diseases. Cholesterol and blood pressure lowering are indicated for the prevention of cardiovascular and renal complications.

Fatty liver and alteration of the gut microbiome induced by diallyl disulfide

Diallyl disulfide (DADS) is one of the primary components of garlic and it exhibits a broad range of biological activities. In the present study, the effects of DADS on lipid metabolism and its potential role in the modulation of the gut microbiome were determined. Hematoxylin and eosin and oil-red O staining were used to assess the liver and intestinal tissues of mice treated with DADS. The expression of lipid metabolism-associated genes was measured using reverse transcription-quantitative PCR (RT-qPCR). The effects of DADS on the gut microbiome were measured using 16S recombinant (r)DNA gene analysis. The results revealed that the serum non-esterified free fatty acids, high density lipopro-tein-cholesterol, low density lipoprotein-cholesterol, serum total cholesterol, liver triglyceride and total cholesterol levels of the mice fed with a low-dose of DADS was significantly higher when compared with the control. Hematoxylin and eosin and oil-red O staining demonstrated that DADS induced fatty liver in mice. The results of the RT-qPCR revealed that the expression levels of a number of lipid metabolism-associated genes were altered in the livers of mice treated with DADS.

The 16S rDNA gene analysis demonstrated that the mice fed on a normal diet treated with a low-dose of DADS had decreased levels of bacteria from the Bacteroidetes phyla and increased levels of bacteria from the Firmicutes phyla. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed the top 20 pathways enriched in the low-dose DADS group of mice fed with a normal diet. In the present study, low-dose DADS induced fatty liver and altered the gut micro-biota, similar to the phenotype induced by a high fat diet, by regulating the expression of lipid metabolism associated genes.

Apolipoprotein C-II mimetic peptide is an efficient activator of lipoprotein lipase in human plasma as studied by a calorimetric approach

Elevated plasma triglyceride (TG) levels are associated with higher risk of atherosclerotic cardiovascular disease. One way to reduce plasma TG is to increase the activity of lipoprotein lipase (LPL), the rate limiting enzyme in plasma TG metabolism. An apolipoprotein (apo) C-II mimetic peptide (18A-CII-a) has been recently developed that stimulated LPL activity in vitro and decreased plasma TG concentration in animal models for hypertriglyceridemia. Since this peptide can serve as a new therapeutic approach for treatment of hypertriglyceridemia, we investigated how 18A-CII-a peptide influences LPL activity in human plasma. We used recently described isothermal titration calorimetry based approach to assess the peptide, which enables the analysis in nearly undiluted human plasma. The 18A-CII-a peptide was 3.5-fold more efficient in stimulating LPL activity than full-length apoC-II in plasma sample from normolipidemic individual. Furthermore, 18A-CII-a also increased LPL activity in hypertriglyceridemic plasma samples. Unlike apoC-II, high concentrations of the 18A-CII-a peptide did not inhibit LPL activity. The increase in LPL activity after addition of 18A-CII-a or apoC-II to plasma was due to the increase of the amount of available substrate for LPL. Measurements with isolated lipoproteins revealed that the relative activation effects of 18A-CII-a and apoC-II on LPL activity were greater in smaller size lipoprotein fractions, such as remnant lipoproteins, low-density lipoproteins and high-density lipoproteins. In summary, this report describes a novel mechanism of action for stimulation of LPL activity by apoC-II mimetic peptides.