High-Density Lipoprotein Function Measurement in Human Studies: Focus on Cholesterol Efflux Capacity

Associations of an HDL apolipoproteomic index with cardiometabolic risk factors before and after exercise training in the HERITAGE Family Study

BACKGROUND AND AIMS

Previous studies have derived and validated an HDL apolipoproteomic score (pCAD) that predicts coronary artery disease (CAD) risk. However, the associations between pCAD and markers of cardiometabolic health in healthy adults are not known, nor are the effects of regular exercise on pCAD.

METHODS

A total of 641 physically inactive adults free of cardiovascular disease from the HERITAGE Family Study completed 20 weeks of exercise training. The pCAD index (range 0-100) was calculated using measurements of apolipoproteins A-I, C-I, C-II, C-III, and C-IV from ApoA-I-tagged serum (higher index = higher CAD risk). The associations between pCAD index and cardiometabolic traits at baseline and their training responses were assessed with Spearman correlation and general linear models. A Bonferroni correction of p < 8.9 × 10-04 was used to determine statistical significance.

RESULTS

The mean ± SD baseline pCAD index was 29 ± 32, with 106 (16.5 %) participants classified as high CAD risk. At baseline, pCAD index was positively associated with blood pressure, systemic inflammation, and body composition. HDL size, VO2max, and HDL-C were negatively associated with pCAD index at baseline. Of those classified as high CAD risk at baseline, 52 (49 %) were reclassified as normal risk after training. Following training, pCAD index changes were inversely correlated (p < 1.4 × 10-04) with changes in HDL-C, HDL size, and LDL size.

CONCLUSIONS

A higher pCAD index was associated with a worse cardiometabolic profile at baseline but improved with regular exercise. The results from this study highlight the potential role of HDL apolipoproteins as therapeutic targets for lifestyle interventions, particularly in high-risk individuals.

Neutrophil/HDL-C, Lymphocyte/HDL-C and Monocyte/HDL-C in subjects with asymptomatic carotid atherosclerosis

BACKGROUND

Leukocyte count is a prognostic marker for cardiovascular diseases, with key role in atherosclerosis development. Specific number of neutrophils, lymphocytes and monocytes can predict cardiovascular risk, also in asymptomatic subjects. Among the lipoprotein fractions, HDL-C is a protective factor in the cardiovascular disorders. For the above reason, we have examined the peripheral count of leukocytes, neutrophils, lymphocytes and monocytes, and the ratios between neutrophils/HDL-cholesterol, lymphocytes/HDL-cholesterol, and monocytes/HDL-cholesterol, to evaluate the possible utility of the obtained values in progression of asymptomatic carotid atherosclerosis.

METHODS

We performed our analysis in a cohort of 100 subjects with asymptomatic carotid atherosclerosis, of which 43 men and 57 women. The data were expressed as medians and IQR. To analyse the differences in leukocyte, neutrophil, lymphocyte, monocytes count and their ratio with HDL-cholesterol the Mann-Whitney test was employed.

RESULTS

The peripheral count of leukocyte subtypes and the ratios, they change in relation to the number of cardiovascular risk factors and the degree of insulin resistance.

CONCLUSIONS

In this cohort of subjects, the percentage of observed cardiovascular risk factors significantly affect some leukocyte parameters. These results, allow us to underline the importance of the leukocyte indices in the evaluation of subjects with asymptomatic vascular atherosclerosis.

The association between lymphocyte to high-density lipoprotein ratio and depression: Data from NHANES 2015-2018

INTRODUCTION

The relationship of lymphocyte to high-density lipoprotein ratio (LHR) with depression remains uncertain. We aimed to evaluate the association between LHR and depression in US adults.

METHODS

In this cross-sectional study, a total of 4216 participants were enrolled from the National Health and Nutrition Examination Survey (2015-2018). Depressive symptoms were measured with the Patient Health Questionnaire-9 (PHQ-9). Participants were classified as having depression if PHQ-9 scores were ≥10. Multiple logistic regression models were used to explore the relationship between the LHR and depression.

RESULTS

Overall, the LHR was significantly associated with depression (per standard deviation increment; adjusted odds ratio (OR), 1.31; 95% confidence interval (CI) [1.14, 1.50]) after adjusted potential variables. Interactions between LHR with metabolic syndrome (MetS) and body mass index (BMI) on the risk of depression were found in stratified analysis (p for interaction < .05).

CONCLUSIONS

A higher level of LHR was significantly associated with higher odds of having depression in US adults, and it was strengthened in participants with MetS or BMI ranging from 25 to 30 kg/m2 .

Complete Blood Count (CBC)-Derived Inflammation Indexes Are Useful in Predicting Metabolic Syndrome in Adults with Severe Obesity

Background: Metabolic syndrome (MetS) is a globally increasing pathological condition. Recent research highlighted the utility of complete blood count-derived (CBC) inflammation indexes to predict MetS in adults with obesity. Methods: This study examined CBC-derived inflammation indexes (NHR, LHR, MHR, PHR, SIRI, AISI, and SII) in 231 adults with severe obesity (88 males, 143 females; age: 52.3 [36.4-63.3] years), divided based on the presence (MetS+) or absence (MetS-) of MetS. The relationships between the indexes and the cardiometabolic risk biomarkers HOMA-IR, TG/HDL-C, and non-HDL-C were also evaluated. Results: Individuals with metabolic syndrome (MetS+) had significantly higher values of MHR, LHR, NHR, PHR, and SIRI than those without (MetS-) (MHR and NHR: p < 0.0001; LHR: p = 0.001; PHR: p = 0.011; SIRI: p = 0.021). These values were positively correlated with the degree of MetS severity. Logistic regression (MHR and NHR: p = 0.000; LHR: p = 0.002; PHR: p = 0.022; SIRI: p = 0.040) and ROC analysis (MHR: AUC = 0.6604; LHR: AUC = 0.6343; NHR: AUC = 0.6741; PHR: AUC = 0.6054; SIRI: AUC = 0.5955) confirmed the predictive potential of CBC-derived inflammation indexes for MetS in individuals with severe obesity. CBC-derived inflammation indexes also correlated with HOMA-IR (MHR, LHR, and NHR: p < 0.0001; PHR: p < 0.001; SIRI: p = 0.000) and TG/HDL-C (MHR, LHR, NHR and PHR: p < 0.0001; SIRI: p = 0.006). Conclusions: In conclusion, this study validates CBC-derived inflammation indexes for predicting MetS in individuals with severe obesity. The relationships between these indexes and cardiometabolic risk factors can enable clinicians to better grade MetS associated with obesity.

Dyslipidemias: Prevalence and Associated Factors among Lactating Women in a Lower- and Middle-Income Country, Ghana

Background

Dyslipidemia, an abnormally high level of lipids in the blood, has a negative impact on the health status of the individual and has lately emerged as a major public health concern, especially for low- and middle-income countries (LMIC) globally, including Ghana. However, it is still unclear what the burden and drivers of these lipid abnormalities are, especially among lactating women in the Upper West of Ghana. Thus, this study is aimed at determining the prevalence of dyslipidemia and its associated factors among lactating mothers in the Wa Municipality of Ghana. Methodology. A cross-sectional study was conducted from May to June 2020 in 8 health facilities within the Wa Municipality. Multistage and simple random sampling methods were used to select the facilities and the 200 study subjects. Sociodemographic data were collected using questionnaires, while blood samples were taken to determine the lipid profile of participants. Dietary patterns were also assessed using the Food Frequency Questionnaire (FFQ). Data were processed and analyzed using SPSS 17 software (SPSS, Inc., Chicago, IL). The chi-square test and multiple regression analysis were performed to determine the predictors associated with the various types of dyslipidemia, with statistical significance set at a p value < 0.05.

Results

The prevalence of hypercholesterolemia (LDL-C), hypo-HDL-cholesterolemia, and hypertriglyceridemia (TG) was 57%, 59%, and 22%, respectively. Chi-square and multinomial regression analysis revealed that duration of lactation (X2 = 3.95, p = 0.047), religion (AOR = 0.375, 95% CI 0.144-0.978, p = 0.045), low income (AOR = 0.116, 95% CI 0.026-0.514, p = 0.005), middle income (AOR = 0.163, 95% CI 0.044-0.600, p = 0.006), and alcohol intake (AOR = 6.312, 95% CI 1.108-35.949, p = 0.038) were associated with LDL-C, while age (AOR = 0.963, 95% CI 0.910-1.019, p < 0.001) and educational status (AOR = 0.365, 95% CI 0.140-0.954, p = 0.040) predicted HDL status.

Conclusion

Dyslipidemia is common among lactating mothers of Wa Municipality, and it is predicted by lifestyle factors. Furthermore, future research to look at a larger sample size on dyslipidemia during lactation is recommended.

The newly proposed alanine aminotransferase to high-density lipoprotein cholesterol ratio has shown effectiveness in identifying non-alcoholic fatty liver disease

Objective

Alanine aminotransferase (ALT) and high-density lipoprotein cholesterol (HDL-C) are important predictive factors for non-alcoholic fatty liver disease (NAFLD). The aim of this study was to analyze the association between the ALT/HDL-C ratio and NAFLD.

Methods

We conducted a retrospective analysis of data from 14,251 individuals participating in the NAGALA project's health screening program. The presence of NAFLD was diagnosed based on the participants' alcohol consumption status and liver ultrasonography images. Multivariable logistic regression models were used to assess the association between the ALT/HDL-C ratio and NAFLD. Receiver operating characteristic (ROC) analysis was performed to determine and compare the effectiveness of ALT, HDL-C, the aspartate aminotransferase to HDL-C (AST/HDL-C) ratio, the gamma-glutamyl transferase to HDL-C (GGT/HDL-C) ratio and the ALT/HDL-C ratio in identifying NAFLD.

Results

We observed a significant positive association between the ALT/HDL-C ratio and the prevalence of NAFLD. For each standard deviation (SD) increase in the ALT/HDL-C ratio, the adjusted odds ratio (OR) for NAFLD among the participants was 3.05 [95% confidence interval (CI): 2.63, 3.53], with the highest quartile of ALT/HDL-C ratio having a 9.96-fold increased risk compared to the lowest quartile. In further subgroup analyses stratified by gender, age, and waist circumference (WC), we observed a significantly higher risk of NAFLD associated with the ALT/HDL-C ratio among individuals aged ≥45 years, males, and those who were abdominal obesity. Furthermore, based on the results of ROC analysis, we found that the ALT/HDL-C ratio [area under the curves (AUC): 0.8553] was significantly superior to ALT, HDL-C, AST/HDL-C ratio and GGT/HDL-C ratio in identifying NAFLD (All Delong P<0.05); the threshold of suggested ALT/HDL-C ratio for identifying NAFLD was 15.97.

Conclusion

This population-based study demonstrates a positive association between the ALT/HDL-C ratio and NAFLD. The ALT/HDL-C ratio can effectively identify individuals with NAFLD.

Fully automated immunoassay for cholesterol uptake capacity to assess high-density lipoprotein function and cardiovascular disease risk

High-density lipoprotein (HDL) cholesterol efflux capacity (CEC), which is a conventional metric of HDL function, has been associated with coronary heart disease risk. However, the CEC assay requires cultured cells and takes several days to perform. We previously established a cell-free assay to evaluate cholesterol uptake capacity (CUC) as a novel measure of HDL functionality and demonstrated its utility in coronary risk stratification. To apply this concept clinically, we developed a rapid and sensitive assay system based on a chemiluminescent magnetic particle immunoassay. The system is fully automated, providing high reproducibility. Measurement of CUC in serum is completed within 20 min per sample without HDL isolation, a notably higher throughput than that of the conventional CEC assay. CUC decreased with myeloperoxidase-mediated oxidation of HDL or in the presence of N-ethylmaleimide, an inhibitor of lecithin: cholesterol acyltransferase (LCAT), whereas CUC was enhanced by the addition of recombinant LCAT. Furthermore, CUC correlated with CEC even after being normalized by ApoA1 concentration and was significantly associated with the requirement for revascularization due to the recurrence of coronary lesions. Therefore, our new assay system shows potential for the accurate measurement of CUC in serum and permits assessing cardiovascular health.

Cholesterol efflux and macrophage polarization in human adipose tissue

The pro-inflammatory status of adipose tissue (AT) has been found to be related to reverse cholesterol transport (RCT) from peritoneal macrophages. However, this finding was made in experimental models using induced peritonitis and isolated peritoneal macrophages of animals. This experimental relationship is in agreement with RCT changes in man in two extreme situations, sepsis or cardiovascular complications. Given the above, we sought to test RTC in relationship to macrophage polarization in the visceral AT (VAT) of living kidney donors (LKDs) and the effect of conditioned media obtained from their AT. The influence of ATCM on CE capacity was first assessed in an experiment where standard plasma was used as cholesterol acceptor from [14C] cholesterol labeled THP-1 cells. Conditioned media as a product of LKDs’ incubated AT showed no effect on CE. Likewise, we did not find any effect of individual plasma of LKDs on CE when individual plasma of LKDs were used as acceptors. On the other hand, we documented an effect of LKDs’ adipose cell size on CE. Our results indicate that the pro-inflammatory status of human AT is not likely induced by disrupted RCT but might be influenced by the metabolic status of LKDs’ adipose tissue.

Cholesterol efflux and macrophage polarization in human adipose tissue

The pro-inflammatory status of adipose tissue (AT) has been found to be related to reverse cholesterol transport (RCT) from peritoneal macrophages. However, this finding was made in experimental models using induced peritonitis and isolated peritoneal macrophages of animals. This experimental relationship is in agreement with RCT changes in man in two extreme situations, sepsis or cardiovascular complications. Given the above, we sought to test RTC in relationship to macrophage polarization in the visceral AT (VAT) of living kidney donors (LKDs) and the effect of conditioned media obtained from their AT. The influence of ATCM on CE capacity was first assessed in an experiment where standard plasma was used as cholesterol acceptor from [14C] cholesterol labeled THP-1. Conditioned media as a product of LKDs' incubated AT showed no effect on CE. Likewise, we did not find any effect of individual plasma of LKDs on CE when individual plasma of LKDs were used as acceptors. On the other hand, we documented an effect of LKDs' adipose cell size on CE. Our results indicate that the pro-inflammatory status of human AT is not likely induced by disrupted RCT but might be influenced by the metabolic status of LKDs' adipose tissue.

Oxidative modification of HDL by lipid aldehydes impacts HDL function

Reduced levels of high-density lipoprotein (HDL) cholesterol correlate with increased risk for atherosclerotic cardiovascular diseases and HDL performs functions including reverse cholesterol transport, inhibition of lipid peroxidation, and suppression of inflammation, that would appear critical for cardioprotection. However, several large clinical trials utilizing pharmacologic interventions that elevated HDL cholesterol levels failed to provide cardioprotection to at-risk individuals. The reasons for these unexpected results have only recently begun to be elucidated. HDL cholesterol levels and HDL function can be significantly discordant, so that elevating HDL cholesterol levels may not necessarily lead to increased functional capacity, particularly under conditions that cause HDL to become oxidatively modified, resulting in HDL dysfunction. Here we review evidence that oxidative modifications of HDL, including by reactive lipid aldehydes generated by lipid peroxidation, reduce HDL functionality and that dicarbonyl scavengers that protect HDL against lipid aldehyde modification are beneficial in pre-clinical models of atherosclerotic cardiovascular disease.

High-density lipoprotein cholesterol efflux capacity in patients with obstructive sleep apnea and its relation with disease severity

Background

Obstructive sleep apnea (OSA) is linked to an accelerated risk of cardiovascular disease (CVD). Some key CVD risk factors are present in patients suffering from OSA such as hypertension, inflammation, oxidative stress, and dyslipidemia. High-density lipoprotein (HDL) cholesterol efflux capacity (CEC) is proposed as a reliable biomarker of HDL function and the present study aimed to quantify this biomarker in patients with OSA.

Methods

ATP binding cassette subfamily A member 1 (ABCA1), non-ABCA1, and total CEC were determined in 69 polysomnographic-confirmed OSA patients and 23 controls. Moreover, paraoxonase (PON) activities, high-sensitivity C-reactive protein (hsCRP), apolipoprotein B (apo B), and apolipoprotein A-I (apo A-I) circulating levels were quantified in the studied population.

Results: All CEC measures were reduced in the OSA group compared to the control group. Strikingly, ABCA1 CEC was diminished in severe OSA in comparison with mild OSA. Furthermore, PON activities and apo A-I showed lower levels, while hsCRP and apo B were elevated in OSA patients compared to controls. Moreover, ABCA1 CEC showed an inverse association with hsCRP and a positive association with apo A-I, while non-ABCA1 CEC presented an association with HDL-C.

Conclusion

These results suggest the presence of an impaired HDL function in OSA. In particular, ABCA1 CEC was associated with disease severity and inflammation which could be a factor increasing the risk of CVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01723-w.

Neutrophil to High-Density Lipoprotein Ratio is Associated with Hemorrhagic Transformation in Patients with Acute Ischemic Stroke

BACKGROUND

Hemorrhagic transformation (HT) is one of the most common and severe complications in patients with acute ischemic stroke (AIS). It indicates a poor prognosis in AIS patients. However, the association of neutrophil to high-density lipoprotein ratio (NHR) with HT remains unclear.

PURPOSE

This study examined whether the NHR has a predictive effect on HT in AIS patients and explored the predictive cutoff value of the NHR.

METHODS

This is a retrospective study and consecutively included AIS patients admitted to the Department of Neurology of the First Affiliated Hospital of Wannan Medical College between December 2019 and January 2022. All subjects had blood samples collected within 24 h of admission, and neutrophil counts and high-density lipoprotein counts were detected. HT was diagnosed with hemorrhage on subsequent magnetic resonance imaging (MRI) or computed tomography (CT) of the brain. Univariate logistic regression analysis was performed to identify confounding factors, and multivariate logistic regression analysis determined the correlation between NHR and HT. Receiver operating characteristic (ROC) curves were used to evaluate the clinical predictive value of NHR.

RESULTS

A total of 725 patients were finally included in this study, of which 87 (12%) developed HT. The median NHR value in the HT group was 4.31, which was significantly higher than that in the non-HT group, and the difference was statistically significant [4.31 (3.54-6.24) vs 3.63 (2.68-4.64), p < 0.001]. The binary logistic regression analysis showed that NHR was independently associated with HT in AIS patients (OR: 1.180, 95% CI: 1.036-1.344, p = 0.013). The area under ROC curve (AUC) of NHR for predicting HT in AIS patients was 0.633 (95% CI: 0.567-0.699, p < 0.001), and its optimal cutoff were 3.52.

CONCLUSION

The NHR was a reliable and simple independent predictor of HT in AIS patients.

Effect of thyroid function on pre-β1 high-density lipoprotein levels in patients with Graves' disease undergoing radioiodine treatment

CONTEXT

The metabolism of HDL is altered in thyroid dysfunctions. Preβ-1 HDL is a very small discoidal precursor HDL and promotes cholesterol efflux via ABCA₁. The effects of thyroid dysfunctions on pre-β1 HDL are unknown. Thyroid hormone regulates ANGPTL3 expression, which may participate in HDL metabolism in thyroid dysfunctions.

OBJECTIVE

To determine the variation of HDL subfractions, especially preβ-1 HDL in thyroid dysfunctions, and whether ANGPTL3 mediates the effect of thyroid function on HDL metabolism.

METHODS

We recruited 26 patients with Graves' disease undergoing radioiodine treatment. They were evaluated at three time points: at baseline, when they were hypothyroid after radioiodine treatment, and when they were on stable levothyroxine replacement and euthyroid.

RESULTS

The concentrations of smaller HDL particles Preβ-1 HDL and HDL3 were highest at the hyperthyroid state, and lowest at the hypothyroid state. While the larger HDL particles HDL2 and HDL1 changed just the opposite. Preβ1-HDL and HDL3 were positively correlated to fT₃ and fT₄, while were negatively correlated to TSH. In contrast, HDL1 was negatively associated with fT₃ and fT₄, while was positively associated with TSH. The correlations between thyroid hormones and HDL subfractions remained significant after adjusting for ANGPTL3.

CONCLUSIONS

There is a shift form smaller HDL particles pre-β1 HDL and HDL3 to larger HDL particles HDL2 and HDL1 in hypothyroidism, while the change is just the opposite in hyperthyroidism. In future, cholesterol efflux capacity should be measured to determine if the function of HDL particles also changes with the shifting of HDL subfractions.

High-density lipoprotein lipid peroxidation as a diagnostics biomarker in coronary artery disease

This study aimed at evaluating the serum High-density lipoprotein lipid peroxidation (HDLox) levels and their association with coronary artery disease (CAD). This case-control study comprised 572 patients with stable CAD and 281 healthy subjects with no history of cardiovascular disease (control group). Based on the results of coronary angiography, the patient group was divided into two groups: CAD- and CAD+. HDLox was measured using a fluorimetric method. The ability of HDLox and serum high-density lipoprotein cholesterol (HDL-C) to detect CAD and coronary artery stenosis ≥50% was also compared using the receiver operating characteristic (ROC) curve analysis. The CAD patients showed significantly higher serum HDLox levels, compared to the control group [1.15 (1.01-1.31) vs. 0.85 (0.62-1.06), no units, p < 0.001]. Moreover, serum HDLox levels were significantly lower in CAD- patients, compared to the CAD+ patients [1.05 (0.92-1.22) vs. 1.24 (1.12-1.35), no units, p < 0.001]. According to the results of univariate and multivariate logistic regression, the HDLox showed association with the presence of CAD (odds ratio [OR]: 1.754; 95% confidence interval [CI]: 1.564-1.968; p < 0.001) and coronary artery stenosis ≥50% (OR: 1.729; 95% CI: 1.534-1.949; p < 0.001). The results obtained from the area under the ROC curve revealed that the HDLox could better detect the risk of CAD and coronary artery stenosis ≥50% compared to serum HDL-C level. The oxidation of HDL leads to a reduction in its antioxidant function and it has a crucial role in the development of atherosclerosis. HDLox is suggested as a diagnostics biomarker for CAD.

Predictive Value of Immune Cells in the Risk of Gestational Diabetes Mellitus: A Pilot Study

Aims

Immunological and biochemical parameters are gaining more and more importance in the prognosis of diabetes and its complications. Here, we assessed the predictive power of immune cells correlated with biochemical parameters in gestational diabetes mellitus (GDM).

Materials and Methods

Immune cells and serum biochemical parameters were determined in women with GDM and pregnant controls. Receiver operating characteristics (ROC) curve analyses were conducted to assess the optimal cutoff and value of ratios of immune cells to biochemical parameters for predicting GDM.

Results

Blood glucose, total cholesterol, LDL-cholesterol and triglycerides were significantly increased whereas HDL-cholesterol decreased in women with GDM compared to pregnant controls. Glycated hemoglobin, creatinine, transaminase activities did not significantly differ between both groups. Total leukocyte, lymphocyte and platelet numbers were significantly high in women with GDM. Correlation tests showed that ratios of lymphocyte/HDL-C, monocyte/HDL-C and granulocyte/HDL-C were significantly higher in women with GDM than in pregnant controls (p = 0.001; p = 0.009 and p = 0.004 respectively). Women with a lymphocyte/HDL-C ratio greater than 3.66 had a 4-fold increased risk of developing GDM than those with lower ratios (odds ratio 4.00; 95% CI: 1.094 – 14.630; p=0.041).

Conclusion

Our study showed that ratios of lymphocyte, monocyte and granulocyte to HDL-C might represent valuable biomarkers for GDM and in particular, lymphocyte/HDL-C ratio exhibited a strong predictive power for GDM risk.

CSL112 (Apolipoprotein A-I [Human]) Strongly Enhances Plasma Apoa-I and Cholesterol Efflux Capacity in Post-Acute Myocardial Infarction Patients: A PK/PD Substudy of the AEGIS-I Trial

Introduction:

Cholesterol efflux capacity (CEC) is impaired following acute myocardial infarction (AMI). CSL112 is an intravenous preparation of human plasma-derived apoA-I formulated with phosphatidylcholine (PC). CSL112 is intended to improve CEC and thereby prevent early recurrent cardiovascular events following AMI. AEGIS-I (ApoA-I Event Reducing in Ischemic Syndromes I) was a multicenter, randomized, double-blind, placebo-controlled, dose-ranging phase 2b study, designed to evaluate the hepatic and renal safety of CSL112. Here, we report an analysis of a pharmacokinetic (PK) and pharmacodynamic (PD) substudy of AEGIS-I.

Methods:

AMI patients were stratified by renal function and randomized 3:3:2 to 4, weekly, 2-hour infusions of low- and high-dose (2 g and 6 g) CSL112, or placebo. PK/PD assessments included plasma concentrations of apoA-I and PC, and measures of total and ABCA1-dependent CEC, as well as lipids/lipoproteins including high density lipoprotein cholesterol (HDL-C), non-HDL-C, low density lipoprotein cholesterol (LDL-C), ApoB, and triglycerides. Inflammatory and cardio-metabolic biomarkers were also evaluated.

Results:

The substudy included 63 subjects from AEGIS-I. CSL112 infusions resulted in rapid, dose-dependent increases in baseline corrected apoA-I and PC, which peaked at the end of the infusion (Tmax ≈ 2 hours). Similarly, there was a dose-dependent elevation in both total CEC and ABCA1-mediated CEC. Mild renal impairment did not affect the PK or PD of CSL112. CSL112 administration was also associated with an increase in plasma levels of HDL-C but not non-HDL-C, LDL-C, apoB, or triglycerides. No dose-effects on inflammatory or cardio-metabolic biomarkers were observed.

Conclusion:

Among patients with AMI, impaired CEC was rapidly elevated by CSL112 infusions in a dose-dependent fashion, along with an increase in apoA-I plasma concentrations. Findings from the current sub-study of the AEGIS-I support a potential atheroprotective benefit of CSL112 for AMI patients.

A Fluorescence-Based In Vitro Method to Assess Cholesterol Efflux

Cholesterol efflux (ChE) capacity is associated with the incidence of cardiovascular events and has been proposed as an emerging cardiovascular risk factor. ChE has been traditionally assessed by in vitro radioactive methods but these are not appropriate when assessing a large number of samples. Therefore, alternative, reproducible nonradioactive methods have been developed. This chapter describes a robust nonradioactive method using a fluorescent tracer to assess ChE in vitro.The measurement of ChE in vitro requires three main components: a cholesterol-loaded donor cell, a cholesterol tracer, and a cholesterol acceptor. This method involves labeling of murine macrophage J774A.1 cells using the fluorescent sterol dipyrromethene boron difluoride (BODIPY)-cholesterol. The cholesterol acceptors from humans or animals include lipid-free apolipoprotein (ApoA)-1, high-density lipoprotein (HDL), HDL₂ and HDL₃ subfractions, serum, plasma or ApoB-depleted serum or plasma. While lipid-free ApoA-1 mediates ChE via only ATP-binding cassette (ABC)A1 transporter, the remaining acceptors mediate ChE via ABCA1 , ABCG1 and scavenger receptor class B type 1 (SRB1) transporters. The reproducibility of this BODIPY-ChE assay is excellent as the intra-assay coefficients of variation (CVs) were <10% (30 replicates on the same day) and the interassay CVs were <14% (10 experiments performed on different days, with 3 replicates each). The fluorescent method therefore represents a reproducible, safe and useful tool to evaluate ChE as an emerging cardiovascular risk factor.

A pilot study of the effects of crocin on high-density lipoprotein cholesterol uptake capacity in patients with metabolic syndrome: A randomized clinical trial

A randomized clinical trial high-density lipoprotein (HDL) cholesterol uptake capacity (CUC) is reduced in patients with metabolic syndrome (MetS). We have assessed the effect of crocin supplementation on HDL CUC in patients with MetS. Forty-four subjects with MetS were randomly allocated to one of two groups: one group received placebo and the other group received crocin at a dose of 30 mg (two tablets of 15 mg per day) for 8 weeks. Serum biochemical parameters were measured using an AutoAnalyzer BT3000 (BioTechnica). The modified CUC method is a cell free, simple, and high-throughput assay that used to evaluate HDL CUC of serum samples. The decision tree analysis was undertaken using JMP Pro (SAS) version 13. The mean age of the crocin and placebo groups were 38.97 ± 13.33 and 43.46 ± 12.77 years, respectively. There was a significant increase in serum HDL CUC in the crocin group compared to that of the placebo group in patients with MetS (p-value< 0.05). The decision tree analysis showed that serum HDL functionality was more important variable than HDL-C level in predicting patients with hypertension at baseline (p-value < 0.05). Crocin administration (30 mg for a period of 8 weeks) was found to improve serum HDL CUC in patients with MetS. TRIAL REGISTRATION: IRCT2013080514279N1.

HDL and reverse cholesterol transport in humans and animals: Lessons from pre-clinical models and clinical studies

The ability to accept cholesterol from cells and to promote reverse cholesterol transport (RCT) represents the best characterized antiatherogenic function of HDL. Studies carried out in animal models have unraveled the multiple mechanisms by which these lipoproteins drive cholesterol efflux from macrophages and cholesterol uptake to the liver. Moreover, the influence of HDL composition and the role of lipid transporters have been clarified by using suitable transgenic models or through experimental design employing pharmacological or nutritional interventions. Cholesterol efflux capacity (CEC), an in vitro assay developed to offer a measure of the first step of RCT, has been shown to associate with cardiovascular risk in several human cohorts, supporting the atheroprotective role of RCT in humans as well. However, negative data in other cohorts have raised concerns on the validity of this biomarker. In this review we will present the most relevant data documenting the role of HDL in RCT, as assessed in classical or innovative methodological approaches.

Serum HDL cholesterol uptake capacity in subjects from the MASHAD cohort study: Its value in determining the risk of cardiovascular endpoints

BACKGROUND

The efficiency of high-density lipoprotein (HDL) to efflux cholesterol contributes to the reverse cholesterol transport (RCT) pathway as one of HDL's proposed functions and depends on the ability of HDL to uptake cholesterol. We aimed to investigate cholesterol uptake capacity (CUC) by a newly developed assay in samples from the MASHAD (Mashhad Stroke and Heart Atherosclerotic Disorders) cohort study.

METHOD

The study population comprised 153 individuals developed CVD diagnosed by a specialist cardiologist, over 6 years of follow-up, and 350 subjects without CVD. We used a modified CUC method to evaluate the functionality of HDL in serum samples.

RESULT

The CUC assay was highly reproducible with values for inter- and intra-assay variation of 13.07 and 6.65, respectively. The mean serum CUC was significantly lower in the CVD group compared to control (p = 0.01). Although, there were no significant differences in serum HDL-C between the groups and there was no significantly association with risk of progressive CVD. Multivariate logistic regression analysis showed that there was a significantly negative association between CUC and risk of CVD after adjustment for confounding parameters (OR = 0.57, 95% CI = 0.38-0.87, p = 0.009). The CUC was also inversely and independently associated with the risk of CVD event using Cox proportional hazards models analysis (HR = 0.62; 95% CI = 0.41-0.94, p = 0.02). We determined the optimum cutoff value of 1.7 a.u for CUC in the population. Furthermore, the CUC value was important in determining the CVD risk stratification derived from data mining analysis.

CONCLUSIONS

Reduced HDL functionality, as measured by CUC, appears to predict CVD in population sample from north-eastern Iran.

[Plasma high density lipoproteins phospholipds as an indirect indicator of their cholesterol efflux capacity - new suspected atherosclerosis risk factor]

High density lipoproteins (HDL) are a unique natural structure, protecting the body from the development of atherosclerotic vascular lesions and cardiovascular diseases due to this ability to remove cholesterol from cells. Plasma HDL level estimated by their cholesterol content, is a common lipid parameter, and its decrease is considered as an established atherosclerosis risk factor. However, a number of studies have shown the absence of positive clinical effects after drug-induced increase in HDL cholesterol. There is increasing evidence that not only HDL concentration, but also HDL properties, considered in this review are important. Many studies showed the decrease of HDL cholesterol efflux capacity in patients with coronary heart diseases and its association with disease severity. Some authors consider a decrease of this HDL capacity as a new additional risk factor of atherosclerosis. The review summarizes existing information on various protein and lipid components of HDL with a primary emphasis on the HDL. Special attention is paid to correlation between the HDL cholesterol efflux capacity and HDL phospholipids and the ratio "phospholipids/free cholesterol". The accumulated information indicates importance of evaluation in the HDL fraction not only in terms of their cholesterol, but also phospholipids. In addition to the traditionally used lipid criteria, this would provide more comprehensive information about the activity of the reverse cholesterol transport process in the body and could contribute to the targeted correction of the detected disorders.

The combined adverse effects of cis-bifenthrin and graphene oxide on lipid homeostasis in Xenopus laevis

Simultaneous exposure to multiple pollutants has received great concerns considering that the interactions between pollutants can alter the environment fate and bioavailability of pollutants with potentially deleterious effects. Graphene oxide (GO) has been widely used in many areas including environmental remediation, biology and agriculture. However, researchers have largely ignored the combined toxicity of GO with coexisting toxicants. Cis-bifenthrin (cis-BF), a typical synthetic pyrethroid insecticide, was frequently detected in the environment, which raised the possibility of interaction between cis-BF and GO. Our study investigated the toxic effects of cis-BF alone or combined with GO on the lipid homeostasis in Xenopus laevis. Tadpoles at 51 stage were exposed to cis-BF (0, 12, 60 and 300 ng/L) or in their combination with GO (0.1 mg/L) for 21 days. Coexposure to cis-BF and GO deteriorated the lipid homeostasis disruption in tadpoles. The up- or down-regulation of lipogenesis genes expression and enzymes activity were amplified in the coexposure groups. Furthermore, the presence of GO enhanced the deleterious impacts of cis-BF on the hepatic function in tadpoles. This study uniquely shows that GO promotes the lipotoxicity and hepatic function deficit caused by cis-BF exposure in frog.

Relationship between neutrophils to HDL-C ratio and severity of coronary stenosis

Background

Lipid and inflammatory molecules play a key role in the development of inflammation. Neutrophil counts are used as markers of inflammation duration, and HDL-C is used as an anti-atherosclerosis component. However, few studies have been found to integrate these two indicators to explore coronary stenosis. We suggested that neutrophil count as a marker of inflammation persistence and HDL-C as an anti-atherosclerotic component should be integrated into a single biomarker NHR to explore its correlation with CAD degree and predict the severity of coronary stenosis among CAD patients.

Methods

We examined 404 eligible patients who underwent coronary angiography. Based on the results of coronary angiography, patients in CAD⁺ group (n = 155) were defined as those having angiographic coronary stenosis of at least 50% lumen reduction in at least one major coronary artery (including left anterior descending artery, left circumflex artery, left main coronary artery, right coronary artery). Patients with luminal stenosis but no more than 50% were defined as CAD⁻ group (n = 49), and patients without luminal stenosis (n = 200) were regarded as control group. The relationship between various serum markers and the severity of coronary stenosis was examined by Spearman correlation analysis. Logistic regression analysis was performed to identify the influencing factors of the severity of coronary artery disease.

Results

The modified Gensini score was positively correlated with neutrophil HDL-C ratio and negatively correlated with albumin and HDL-C. Multiple regression analysis showed that neutrophil HDL-C ratio were significantly associated with CAD. Neutrophil HDL-C ratio is an independent predictor of CAD. The ROC analysis provided a cut-off value of 1.51 for neutrophil HDL-C ratio to predict CAD with 94.8% sensitivity and 0.024 Yoden index, and area under the ROC curve of 0.617 (95% CI 0.560–0.675, P < 0.001).

Conclusion

Neutrophil HDL-C ratio is not only closely related to coronary artery stenosis, but also an independent predictor of severe coronary stenosis.

Low-density lipoprotein nanomedicines: mechanisms of targeting, biology, and theranostic potential

Native nanostructured lipoproteins such as low- and high-density lipoproteins (LDL and HDL) are powerful tools for the targeted delivery of drugs and imaging agents. While the cellular recognition of well-known HDL-based carriers occurs via interactions with an HDL receptor, the selective delivery and uptake of LDL particles by target cells are more complex. The most well-known mode of LDL-based delivery is via the interaction between apolipoprotein B (Apo-B) - the main protein of LDL - and the low-density lipoprotein receptor (LDLR). LDLR is expressed in the liver, adipocytes, and macrophages, and thus selectively delivers LDL carriers to these cells and tissues. Moreover, the elevated expression of LDLR in tumor cells indicates a role for LDL in the targeted delivery of chemotherapy drugs. In addition, chronic inflammation associated with hypercholesterolemia (i.e., high levels of endogenous LDL) can be abated by LDL carriers, which outcompete the deleterious oxidized LDL for uptake by macrophages. In this case, synthetic LDL nanocarriers act as 'eat-me' signals and exploit mechanisms of native LDL uptake for targeted drug delivery and imaging. Lastly, recent studies have shown that the delivery of LDL-based nanocarriers to macrophages via fluid-phase pinocytosis is a promising tool for atherosclerosis imaging. Hence, the present review summarizes the use of natural and synthetic LDL-based carriers for drug delivery and imaging and discusses various mechanisms of targeting.

Evaluation of the laboratory parameters in hidradenitis suppurativa: Can we use new inflammatory biomarkers?

Hidradenitis suppurativa (HS) is a chronic, recurrent, and debilitating skin disease. Recent studies showed that inflammatory biomarkers, such as neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), Lymphocyte/HDL ratio (LHR), Neutrophil/HDL ratio (NHR), and Monocyte/HDL ratio (MHR) are an indicator of inflammatory diseases and may be associated with disease severity and disease activity. To investigate NLR, PLR, LHR, NHR, and MHR in HS patients. In addition, to compare erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), complete blood count, leukocyte profile, and biochemical parameters between the control and the patient group. Clinical and biochemical data of patients and healthy subjects were collected from medical records, retrospectively. In total, 166 patients with HS and 124 control subjects were included. We found no significant difference in NLR (P = .207) and PLR (P = .257). LHR (P < .001), NHR (P < .001), and MHR (P < .001) were significantly higher in the patient group. No positive correlation was found between any of these markers and disease severity according to Hurley staging system. However, MCV (Mean corpuscular volume), RDW (Red cell distribution width), and CRP showed a significant positive correlation with disease severity. Among these markers, only MHR was positively correlated with disease duration. Our study shows that CRP still maintains its value for HS patients compared to new inflammation markers. Unlike the studies in other inflammatory diseases, no significant relationship was found with most of these inflammatory parameters. MHR may be more useful in patients with HS as an indicator of inflammation compared to other parameters.

Impaired cholesterol efflux capacity in patients with Helicobacter pylori infection and its relation with inflammation

BACKGROUND

Gut microorganisms are associated with atherosclerosis and related cardiovascular disease. Helicobacter pylori (H. pylori) infection is associated with dyslipidemia and inflammation contributing to the progression of atherosclerosis.

OBJECTIVE

Several studies have reported reduced HDL-C levels in H. pylori infected patients, but HDL cholesterol efflux capacity (CEC) as the most important function of HDL has not been evaluated yet.

METHODS

This cross-sectional study was conducted with 44 biopsy confirmed H. pylori patients and 43 controls. ABCA1-mediated, non-ABCA1 and total CEC were measured in ApoB-depleted serum and levels of ApoA-I, ApoB and hsCRP were estimated using ELISA technique.

RESULTS

Total and ABCA1 mediated-CEC were reduced in patients compared to controls, independent of age, sex, body mass index and HDL-C (p < 0.001), while non-ABCA1 CEC indicated no significant change between the groups. In addition, patients showed lower serum levels of ApoA-I but increased levels of hsCRP when compared to controls. Total CEC and ABCA1-mediated CEC positively correlated with ApoA-I and HDL-C, furthermore, ABCA1-mediated CEC as well as ApoA-I inversely correlated with hsCRP.

CONCLUSION

The results of the present study indicate reduced CECs in H. pylori infected patients, especially ABCA1-mediated CEC which is associated with decreased ApoA-I and increased inflammation.

Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux

Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.

Rate and Extent of Recovery from Reproductive and Cardiac Dysfunction Due to Androgen Abuse in Men

CONTEXT

Androgen abuse impairs male reproductive and cardiac function, but the rate, extent, and determinants of recovery are not understood.

OBJECTIVE

To investigate recovery of male reproductive and cardiac function after ceasing androgen intake in current and past androgen abusers compared with healthy non-users.

METHODS

Cross-sectional, observational study recruited via social media 41 current and 31 past users (≥3 months since last use, median 300 days since last use) with 21 healthy, eugonadal non-users. Each provided a history, examination, and serum and semen sample and underwent testicular ultrasound, body composition analysis, and cardiac function evaluation.

RESULTS

Current abusers had suppressed reproductive function and impaired cardiac systolic function and lipoprotein parameters compared with non- or past users. Past users did not differ from non-users, suggesting full recovery of suppressed reproductive and cardiac functions after ceasing androgen abuse, other than residual reduced testicular volume. Mean time to recovery was faster for reproductive hormones (anti-Mullerian hormone [AMH], 7.3 months; luteinizing hormone [LH], 10.7 months) than for sperm variables (output, 14.1 months) whereas spermatogenesis (serum follicle-stimulating hormone [FSH], inhibin B, inhibin) took longer. The duration of androgen abuse was the only other variable associated with slower recovery of sperm output (but not hormones).

CONCLUSION

Suppressed testicular and cardiac function due to androgen abuse is effectively fully reversible (apart from testis volume and serum sex hormone binding globulin) with recovery taking between 6 to 18 months after ceasing androgen intake with possible cumulative effects on spermatogenesis. Suppressed serum AMH, LH, and FSH represent convenient, useful, and underutilized markers of recovery from androgen abuse.

Lipid efflux mechanisms, relation to disease and potential therapeutic aspects

Lipids are hydrophobic and amphiphilic molecules involved in diverse functions such as membrane structure, energy metabolism, immunity, and signaling. However, altered intra-cellular lipid levels or composition can lead to metabolic and inflammatory dysfunction, as well as lipotoxicity. Thus, intra-cellular lipid homeostasis is tightly regulated by multiple mechanisms. Since most peripheral cells do not catabolize cholesterol, efflux (extra-cellular transport) of cholesterol is vital for lipid homeostasis. Defective efflux contributes to atherosclerotic plaque development, impaired β-cell insulin secretion, and neuropathology. Of these, defective lipid efflux in macrophages in the arterial walls leading to foam cell and atherosclerotic plaque formation has been the most well studied, likely because a leading global cause of death is cardiovascular disease. Circulating high density lipoprotein particles play critical roles as acceptors of effluxed cellular lipids, suggesting their importance in disease etiology. We review here mechanisms and pathways that modulate lipid efflux, the role of lipid efflux in disease etiology, and therapeutic options aimed at modulating this critical process.

High density lipoprotein functionality and cardiovascular events and mortality: A systematic review and meta-analysis

BACKGROUND AND AIMS

The aim of this systematic review and meta-analysis is to synthesize studies assessing the associations between high-density lipoprotein functionality and risk of cardiovascular disease and mortality.

METHODS

We searched Medline and Embase for the identification of observational studies meeting the inclusion criteria. This meta-analysis was conducted following the PRISMA statement and was registered in PROSPERO (CRD42017065857). We pooled risk estimates with a random-effect model separately for cardiovascular disease (fatal and non-fatal) and all-cause mortality.

RESULTS

Out of 29 manuscripts, 20 articles investigated cholesterol efflux capacity (13 prospective and 7 cross-sectional), 10 antioxidant capacity (7 prospective and 3 cross-sectional) and two anti-inflammatory capacity of high-density lipoprotein (1 prospective and 1 cross-sectional). A greater cholesterol efflux capacity was associated with lower risk of cardiovascular disease in 8 studies (RR for 1SD increase: 0.86; 95% CI: 0.76-0.98) and of mortality in 5 studies (RR for 1SD increase: 0,77; 0.60-1.00). Better antioxidant capacity was non-significantly associated with lower cardiovascular disease risk in 2 studies (RR for 1SD increase 0.70; 0.32-1.53) and significantly with mortality in 3 studies (RR for 1SD increase 0.48; 0.28-0.81). High-density lipoprotein anti-inflammatory ability was associated with a lower cardiovascular disease risk in the only prospective study.

CONCLUSIONS

Greater high-density lipoprotein cholesterol efflux capacity and antioxidant/anti-inflammatory capacities were associated with lower risk of cardiovascular disease. However, the heterogeneity between studies and evidence of publication bias warrants caution and highlights the need for larger prospective studies with standardized assays and specific outcomes.

Modulation of cholesterol efflux capacity in patients with myocardial infarction

PURPOSE OF REVIEW

Epidemiologic studies consistently demonstrated that patients with coronary artery disease (CAD) and low HDL cholesterol (HDL-C) are more likely to develop major adverse cardiovascular events as compared with those with normal or high HDL. However, several large randomized trials failed to demonstrate that a substantial, pharmacological-based, increase of HDL-C concentrations results in a clinically significant reduction of ischemic outcomes. This has been largely attributed to the fact that, although these drugs are able to raise the HDL-C concentration, they have no effect on HDL-C atheroprotective function. Subsequently, the 'HDL hypothesis' evolved, and the focus shifted from raising the concentration of HDL-C to raising the reverse cholesterol transport (RCT) function by increasing patients cholesterol efflux capacity (CEC) instead. Indeed, new data suggest that HDL-C metabolism and the ability of the HDL molecule to transport cholesterol from the atherosclerotic plaque to the liver, measured by the CEC, is more important than steady-state HDL-C levels. Modulation of the CEC has become, therefore, a promising therapeutic target in CAD patients. This article reviews the current data on the 'cholesterol efflux hypothesis' and discuss its ability to be modulated has a potential therapeutic target.

RECENT FINDINGS

Recent data have demonstrated that impaired serum CEC was associated with increased mortality after a myocardial infarction (MI). Thus, therapeutic intervention aiming to improve CEC and RCT may reduce the risk of recurrent events. Early phase clinical studies targeting CEC showed promising results and a megatrial is ongoing testing the hypothesis that an improved RCT trough a modulation of the CEC can modify patient's prognosis after an acute MI.

SUMMARY

The 'cholesterol efflux hypothesis' is now supported by several clinical studies and is being tested with a therapeutic candidate in a megatrial enrolling high-risk patient with MI.

LOX-1: A potential driver of cardiovascular risk in SLE patients

Traditional cardiovascular disease (CVD) risk factors, such as hypertension, dyslipidemia and diabetes do not explain the increased CVD burden in systemic lupus erythematosus (SLE). The oxidized-LDL receptor, LOX-1, is an inflammation-induced receptor implicated in atherosclerotic plaque formation in acute coronary syndrome, and here we evaluated its role in SLE-associated CVD. SLE patients have increased sLOX-1 levels which were associated with elevated proinflammatory HDL, oxLDL and hsCRP. Interestingly, increased sLOX-1 levels were associated with patients with early disease onset, low disease activity, increased IL-8, and normal complement and hematological measures. LOX-1 was increased on patient-derived monocytes and low-density granulocytes, and activation with oxLDL and immune-complexes increased membrane LOX-1, TACE activity, sLOX-1 release, proinflammatory cytokine production by monocytes, and triggered the formation of neutrophil extracellular traps which can promote vascular injury. In conclusion, perturbations in the lipid content in SLE patients' blood activate LOX-1 and promote inflammatory responses. Increased sLOX-1 levels may be an indicator of high CVD risk, and blockade of LOX-1 may provide a therapeutic opportunity for ameliorating atherosclerosis in SLE patients.

Roles of Reconstituted High-Density Lipoprotein Nanoparticles in Cardiovascular Disease: A New Paradigm for Drug Discovery

Epidemiological results revealed that there is an inverse correlation between high-density lipoprotein (HDL) cholesterol levels and risks of atherosclerotic cardiovascular disease (ASCVD). Mounting evidence supports that HDLs are atheroprotective, therefore, many therapeutic approaches have been developed to increase HDL cholesterol (HDL-C) levels. Nevertheless, HDL-raising therapies, such as cholesteryl ester transfer protein (CETP) inhibitors, failed to ameliorate cardiovascular outcomes in clinical trials, thereby casting doubt on the treatment of cardiovascular disease (CVD) by increasing HDL-C levels. Therefore, HDL-targeted interventional studies were shifted to increasing the number of HDL particles capable of promoting ATP-binding cassette transporter A1 (ABCA1)-mediated cholesterol efflux. One such approach was the development of reconstituted HDL (rHDL) particles that promote ABCA1-mediated cholesterol efflux from lipid-enriched macrophages. Here, we explore the manipulation of rHDL nanoparticles as a strategy for the treatment of CVD. In addition, we discuss technological capabilities and the challenge of relating preclinical in vivo mice research to clinical studies. Finally, by drawing lessons from developing rHDL nanoparticles, we also incorporate the viabilities and advantages of the development of a molecular imaging probe with HDL nanoparticles when applied to ASCVD, as well as gaps in technology and knowledge required for putting the HDL-targeted therapeutics into full gear.

Correlates and Predictors of Cerebrospinal Fluid Cholesterol Efflux Capacity from Neural Cells, a Family of Biomarkers for Cholesterol Epidemiology in Alzheimer's Disease

BACKGROUND

Basic research has implicated intracellular cholesterol in neurons, microglia, and astrocytes in the pathogenesis of Alzheimer's disease (AD), but there is presently no assay to access intracellular cholesterol in neural cells in living people in the context of AD.

OBJECTIVE

To devise and characterize an assay that can access intracellular cholesterol and cholesterol efflux in neural cells in living subjects.

METHODS

We modified the protocol for high-density lipoprotein cholesterol efflux capacity (CEC) from macrophages, a biomarker that accesses cholesterol in macrophages in atherosclerosis. To measure cerebrospinal fluid (CSF) CECs from neurons, microglia, and astrocytes, CSF was exposed to, correspondingly, neuronal, microglial, and astrocytic cholesterol source cells. Human neuroblastoma SH-SY5Y, mouse microglial N9, and human astroglial A172 cells were used as the cholesterol source cells. CSF samples were screened for contamination with blood. CSF CECs were measured in a small cohort of 22 individuals.

RESULTS

CSF CECs from neurons, microglia, and astrocytes were moderately to moderately strongly correlated with CSF concentrations of cholesterol, apolipoprotein A-I, apolipoprotein E, and clusterin (Pearson's r = 0.53-0.86), were in poor agreement with one another regarding CEC of the CSF samples (Lin's concordance coefficient rc = 0.71-0.76), and were best predicted by models consisting of, correspondingly, CSF phospholipid (R2 = 0.87, p < 0.0001), CSF apolipoprotein A-I and clusterin (R2 = 0.90, p < 0.0001), and CSF clusterin (R2 = 0.62, p = 0.0005).

CONCLUSION

Characteristics of the CSF CEC metrics suggest a potential for independent association with AD and provision of fresh insight into the role of cholesterol in AD pathogenesis.

Comparison of the Value of Neutrophil to High-Density Lipoprotein Cholesterol Ratio and Lymphocyte to High-Density Lipoprotein Cholesterol Ratio for Predicting Metabolic Syndrome Among a Population in the Southern Coast of China

BACKGROUND

This study aimed to determine the optimal cutoff values and evaluate the associations of neutrophil to high-density lipoprotein cholesterol ratio (NHR) and lymphocyte to high-density lipoprotein cholesterol ratio (LHR) with metabolic syndrome (MetS), stratified by sex.

METHODS

A large-scale cross-sectional survey was conducted among 1401 adults from January to April 2018 in six communities in Wanzhai Town, Zhuhai City, on the southern coast of China. Receiver operating characteristics (ROC) analyses and logistic regression analysis were conducted to assess the optimal cutoff and value of NHR and LHR for predicting MetS.

RESULTS

Hematological parameters showed the correlation with the occurrence of MetS (red blood cells, hemoglobin, and white blood cells and subtypes). Binomial logistic regression analysis found that LHR (OR: 3.671; 95% CI: 2.385-5.651; p<0.001) and NHR (OR: 1.728; 95% CI: 1.353-2.207; p<0.001) can predict MetS in females, independent of confounding factors. Although LHR (OR: 1.571; 95% CI: 1.001-2.468; p=0.05) and NHR (OR: 1.163; 95% CI: 0.909-1.48; p<0.01) were independent risk factors for MetS in males after adjustment for age, current smoking, current alcohol use, physical activity,  educational attainment, waist circumference, systolic pressure, diastolic pressure and hypersensitive C-reactive protein (hs-CRP), when further adjusted for fasting plasma glucose level, LHR and NHR, both lost their independence. ROC curves showed that LHR had the highest AUC for predicting MetS in females and NHR had the highest AUC in males. The cutoff points of LHR and NHR were 1.36 and 2.31 in females, and 1.96 and 3.38 in males.

CONCLUSION

LHR and NHR may become valuable makers and have strong predictive power for predicting MetS, especially in females.

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

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

HDL and Reverse Cholesterol Transport Biomarkers

High-density lipoprotein (HDL) is a protein-lipid nanoparticle that has predominately been characterized by its cholesterol concentration (HDL-C). Recent studies have challenged the presumed inverse association between HDL-C and cardiovascular events, suggesting a more U-shaped association. This has opened new opportunities to evaluate more novel measures of HDL metabolism, such as HDL particle number (HDL-P) and one of HDL's key functions, cholesterol efflux. Both HDL-P and cholesterol efflux are inversely associated with incident cardiovascular events and may perhaps be better targets for intervention. This review includes recent research on the emerging U-shaped association between HDL-C and cardiovascular events, recent observational studies related to HDL-P, and the effects of established and novel interventions on cholesterol efflux.

Aerobic Training in Young Men Increases the Transfer of Cholesterol to High Density Lipoprotein In Vitro: Impact of High Density Lipoprotein Size

Exercise training not only improves the plasma lipid profile but also reduces risk of developing coronary heart disease. We investigate whether plasma lipids and high density lipoprotein (HDL) metabolism are affected by aerobic training and whether the high-density lipoprotein cholesterol (HDL-C) levels at baseline influence exercise-induced changes in HDL. Seventy-one male sedentary volunteers were evaluated and allocated in two subgroups, according to the HLD-C levels (< or >40 mg/dL). Participants underwent an 18-week aerobic training period. Blood was sampled before and after training for biochemical analysis. Plasma lipids, apolipoproteins, HDL diameter, and VO₂ peak were determined. Lipid transfers to HDL were determined in vitro by incubating plasma samples with a donor lipid artificial nanoemulsion. After the 18-week period of aerobic training, the VO₂ peak increased, while the mean body mass index (BMI) decreased. HDL-C concentration was higher after the training period, but low-density lipoprotein cholesterol (LDL-C) and non-HDL-C did not change. The transfer of esterified cholesterol and phospholipids was greater after exercise training, but the triacylglycerol and unesterified cholesterol transfers were unchanged. The HDL particle diameter increased after aerobic training in all participants. When the participants were separated in low-HDL and normal-HDL groups, the postaerobic exercise increment in HDL-C was higher in the low-HDL group, while the transfer of esterified cholesterol was lower. In conclusion, aerobic exercise training increases the lipid transfers to HDL, as measured by an in vitro method, which possibly contributes to the classical elevation of the HDL-C associated with training.

Cholesterol efflux capacity, HDL cholesterol, and risk of coronary heart disease: a nested case-control study in men

The capacity of HDLs to accept cholesterol effluxing from macrophages has been proposed as a new biomarker of HDLs' anti-atherogenic function. Whether cholesterol efflux capacity (CEC) is independent of HDL cholesterol (HDL-C) as a biomarker for coronary heart disease (CHD) risk in a generally healthy primary-prevention population remains unanswered. Therefore, in this nested case-control study, we simultaneously assessed CEC (using J774 cells) and plasma HDL-C levels as predictors of CHD in healthy middle-aged and older men not receiving treatment affecting blood lipid concentrations. We used risk-set sampling of participants free of disease at baseline from the Health Professionals Follow-Up Study, and matched cases (n = 701) to controls 1:1 for age, smoking, and blood sampling date. We applied conditional logistic regression models to calculate the multivariable relative risk and 95% CIs of CHD over 16 years of follow-up. CEC and HDL-C were correlated (r = 0.50, P < 0.0001). The risk (95% CI) of CHD per one SD higher CEC was 0.82 (0.71-0.96), but completely attenuated to 1.08 (0.85-1.37) with HDL-C in the model. The association per one SD between HDL-C and CHD (0.66; 0.58-0.76) was essentially unchanged (0.68; 0.53-0.88) after adjustment for CEC. These findings indicate that CEC's ability to predict CHD may not be independent of HDL-C in a cohort of generally healthy men.

High-Density Lipoprotein Functionality as a New Pharmacological Target on Cardiovascular Disease: Unifying Mechanism That Explains High-Density Lipoprotein Protection Toward the Progression of Atherosclerosis

The formation of the atherosclerotic plaque that is characterized by the accumulation of abnormal amounts of cholesterol-loaded macrophages in the artery wall is mediated by both inflammatory events and alterations of lipid/lipoprotein metabolism. Reverse transport of cholesterol opposes the formation and development of atherosclerotic plaque by promoting high density lipoprotein (HDL)-mediated removal of cholesterol from peripheral macrophages and its delivery back to the liver for excretion into the bile. Although an inverse association between HDL plasma levels and the risk of cardiovascular disease (CVD) has been demonstrated over the years, several studies have recently shown that the antiatherogenic functions of HDL seem to be mediated by their functionality, not always associated with their plasma concentrations. Therefore, assessment of HDL function, evaluated as the capacity to promote cell cholesterol efflux, may offer a better prediction of CVD than HDL levels alone. In agreement with this idea, it has recently been shown that the assessment of serum cholesterol efflux capacity (CEC), as a metric of HDL functionality, may represent a predictor of atherosclerosis extent in humans. The purpose of this narrative review is to summarize the current evidence concerning the role of cholesterol efflux capacity that is important for evaluating CVD risk, focusing on pharmacological evidences and its relationship with inflammation. We conclude that HDL therapeutics are a promising area of investigation but strategies for identifying efficacy must move beyond the idea of simply raising static HDL-cholesterol levels and toward methods of measuring the dynamics of HDL particle remodeling and the generation of lipid-free apolipoprotein A-I (apoA-I). In this way, apoA-I, unlike mature HDL, can promote the greatest extent of cholesterol efflux relieving cellular cholesterol toxicity and the inflammation it causes.

Effects of exercise on HDL functionality

PURPOSE OF REVIEW

Low HDL-cholesterol (HDL-C) levels are a strong predictor of cardiovascular disease risk and can be improved with regular exercise. However, raising HDL-C levels pharmacologically has not shown convincing clinical benefits. Thus, research has recently focused on identifying therapies that improve HDL function, with exercise representing such a potential therapy. The purpose of this review is to summarize the effects of exercise interventions on HDL function.

RECENT FINDINGS

The effects of exercise and lifestyle interventions on the primary atheroprotective functions of HDL are reviewed, namely, cholesterol efflux, antioxidative, and anti-inflammatory properties. Differences in study design, study population, and assays are discussed to aid in the interpretation of the reviewed studies.

SUMMARY

There is mixed evidence that regular aerobic exercise improves cholesterol efflux capacity, with recent research suggesting an exercise dose threshold needs to be exceeded to produce beneficial effects. There is preliminary evidence that exercise improves the antioxidative and anti-inflammatory properties of HDL. Although exercise represents a potential therapeutic approach to improve HDL function, the heterogeneity and/or lack of findings warrants more and larger studies to determine what HDL function(s) are most responsive to regular exercise and what dose of exercise elicits the greatest improvements in HDL functionality.

Lymphocyte To High-Density Lipoprotein Ratio As A New Indicator Of Inflammation And Metabolic Syndrome

PURPOSE

Metabolic syndrome (MetS), which is a global public health problem, is a state of chronic low-grade inflammation. This study looked at the changes in hematological parameters and the predictive value of the lymphocyte to high-density lipoprotein cholesterol (HDL-C) ratio (LHR) as a new index in subjects with and without MetS in coastal cities in southern China.

PATIENTS AND METHODS

In this cross-sectional study, there were 852 participants (n = 598 with MetS and n = 254 without MetS). MetS was defined in accordance with the National Cholesterol Education Program, Adult Treatment Panel III (NCEP-ATP III) criteria.

RESULTS

MetS was positively correlated with white blood cell count, total lymphocyte count, neutrophil count, red blood cell count, hematocrit, hemoglobin, and high-sensitivity C-reactive protein levels (p<0.05). In addition, there was a positive correlation between LHR and the number of metabolic risk factors for MetS. In a logistic regression analysis, LHR (odds ratio: 4.117; 95% CI: 2.766-6.309; p<0.001) was an independent predictor of MetS. When a receiver operating characteristic (ROC) curve analysis was used to assess the value of LHR for predicting MetS, the area under the curve yielded a cut-off value of 1.657, with a sensitivity of 65% and a specificity of 64% (p<0.0001).

CONCLUSION

In summary, MetS can involve changes in blood parameters, and LHR may be a useful marker of inflammation to assess the presence and severity of MetS.

Sini Decoction Intervention on Atherosclerosis via PPARγ-LXRα-ABCA1 Pathway in Rabbits

Aim

Sini decoction (SND) is a commonly used herbal formula showing lipid-lowering effects and is applied in traditional Chinese medicine (TCM) for the treatment of cardiovascular disease (CVD) and atherosclerosis (AS). However, the mechanisms behind its anti-atherosclerotic effects are still unknown, and will be investigated in this study.

Methods

AS was induced in rabbits by high fat diet (HFD) and treated with solvent (HFD group), atorvastatin (Ator group), or SND (SND group) for 12 weeks. Healthy rabbits (Chow group) were used as control. Serum and liver homogenates were collected, and lipid profiles as well as serum ApoA-I and ApoB were examined. Histopathological changes and lipid deposition in the proximal aorta and liver were detected by Oil red O staining. Western blot was used to detect the expression of ABCA1, ApoA-I, ApoB, PPARγ, and LXRα in liver, peritoneal macrophages, peripheral mononuclear cells (PMC), and adipose tissues.

Results

SND significantly attenuated the levels of total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol(LDL-C) in serum and liver. However, high density lipoprotein cholesterol (HDL-C) dramatically increased. SND treatment also decreased lipid deposition and improved the structure of the liver and aorta. Furthermore, SND enhanced the expression levels of ABCA1, PPARγ, and LXRα in liver, adipose tissues, PMC, and peritoneal macrophages. It also upregulated hepatic and serum ApoA-I expression and serum ApoA-I/ApoB ratio. CONCLUSIONS:SND treatment relieved AS, improved lipid profiles, and increased serum HDL-C level. The potential mechanism behind this might be the improvement of reverse cholesterol transport (RCT) involved with enhanced expression of ABCA1, ApoA-I, PPARγ, and LXRα.

Feasibility of a plasma bioassay to assess oxidative protection of low-density lipoproteins by high-density lipoproteins

BACKGROUND

Traditionally, the impact of lipoproteins on vascular disease has been evaluated in light of their quantity, that is, cholesterol content, in plasma. However, recent studies of high-density lipoproteins (HDLs) have focused on functionality with regard to atheroprotection. For example, bioassays have emerged to assess the ability of HDL, in its near native plasma environment, to promote cholesterol removal (efflux) from cells. As a result, attention has focused on developing plasma-based assays for other putative HDL protective functions including protecting low-density lipoproteins (LDLs) from oxidative damage.

OBJECTIVE

To determine the feasibility of such an assay in a complex sample such as plasma, we evaluated the contribution of HDL vs other plasma factors in preventing LDL oxidation.

METHODS

We separated normolipidemic human plasma by gel filtration chromatography and assessed each fraction for its ability to prevent LDL modification by water soluble radical and copper-initiated oxidation mechanisms.

RESULTS

Using proteomics and selective precipitation methods, we identified major antioxidative contributions for fibrinogen, immunoglobulin G, albumin, and small soluble molecules like uric acid and ascorbate, with albumin being especially dominant in copper-initiated mechanisms. HDL particles were minor contributors (∼1%-2%) to the antioxidant capacity of plasma, irrespective of oxidation mechanism.

CONCLUSIONS

Given the overwhelming background of antioxidant capacity inherent to highly abundant plasma proteins, specific bioassays of HDL antioxidative function will likely require its complete separation from plasma.

Cholesterol efflux capacity of large, small and total HDL particles is unaltered by atorvastatin in patients with type 2 diabetes

BACKGROUND AND AIMS

Research on the biologic activities of HDL, such as cholesterol efflux capacity and HDL composition, has allowed the understanding of the effect of interventions directed to improve cardiovascular risk. Previously, statin therapy has shown conflicting results about its effects on cholesterol efflux capacity of HDL; the underlying mechanisms are unclear but studies with positive effects are associated with an increase of HDL-cholesterol levels. We investigated if 10 weeks of atorvastatin therapy changes HDL efflux capacity and the chemical composition of its subpopulations.

METHODS

In a before-after design basis, HDL-cholesterol levels, chemical composition and cholesterol efflux capacity from HDL subpopulations isolated by isophynic ultracentrifugation were assessed in plasma samples from 60 patients with type 2 diabetes mellito (T2DM) at baseline and after 10 weeks of treatment with 20 mg atorvastatin. Cholesterol efflux was measured from human THP-1 cells using large, light HDL2b and small, dense 3c subpopulations as well as total HDL as acceptors. Changes of cholesterol efflux and chemical composition of HDL after treatment were analyzed. Correlations among variables potentially involved in cholesterol efflux were evaluated.

RESULTS

A significant decrease of 4% in HDL-cholesterol levels was observed from 47 (42-54) to 45 (39-56) mg/dL, p = 0.02. Cholesterol efflux from total-HDL and HDL2b and 3c subfractions was maintained unchanged after treatment. The total mass of HDL remained unaffected, except for the HDL3a subpopulation accounted for by a significant increase in total protein content. No significant correlations for variables previously known to be associated with cholesterol efflux were found in our study.

CONCLUSIONS

Short therapy of 10 weeks with 20 mg of atorvastatin does not modify the cholesterol efflux capacity neither the total mass of HDL2b, HDL3c and total HDL. The discrepancy with previous reports may be due to the selective effects among different classes of statins or differences in the approaches to measure cellular cholesterol efflux.