Dysfunctional HDL as a Therapeutic Target for Atherosclerosis Prevention

Heterogeneity of diabetic dyslipidemia, data from the NHANES (2011-2016)

Epidemiologic studies have demonstrated that diabetes amplifies the effects of dyslipidemia as a risk factor for cardiovascular disease (CVD). A better understanding of lipid profiles is important for lipid-lowering treatment and reducing cardiovascular risk in populations with diabetes. To describe the dyslipidemia patterns in patient with and without diabetes in the adult US population. Data from National Health and Nutrition Examination Survey (NHANES) 2011 to 2016 was analyzed. Surprisingly, 49.9% of the people with diabetes have both normal triglycerides (TGs) and normal high-density lipoprotein cholesterol (HDL-C). 33.4% of the people with diabetes have elevated TGs and 36.1% of them have low HDL-C. Only 19.3% of them have both elevated TGs and low HDL-C. Among people without diabetes, 67.5% have normal TGs and normal HDL-C, 28.0% have elevated TGs, 23.9% have low HDL-C and 8.8% have both elevated TGs and low HDL-C. The differences in the proportions of individuals with both elevated TGs and low HDL-C between the diabetic group and the nondiabetic group were more obvious in females: 7.7% in women without diabetes and 22.7% in women with diabetes. The proportion of individuals in the TG↑HDL-C↓group in the population with diabetes exhibited a decreasing trend in age groups > 30 years old, and the 30 to 40 years group of individuals with diabetes had the highest proportion of atherogenic dyslipidemia. The low-density lipoprotein cholesterol (LDL-C) to apoB ratio is generally lower in people with diabetes, with the lowest level in the TG↑HDL-C↓group. Dyslipidemia patterns in diabetes patients are highly heterogeneous. Deep phenotyping sub-groups of dyslipidemia is warranted to identify higher-risk patients for evaluation of non-LDL-C therapies. This explained at least partially of the difficult search for novel therapies in the post-LDL-C era.

Dapagliflozin-Induced Myocardial Flow Reserve Improvement is not Associated with HDL Ability to Stimulate Endothelial Nitric Oxide Production

BACKGROUND

Sodium-glucose cotransporter-2 (SGLT2) inhibitors have shown controversial results in modulating plasma lipids in clinical trials. Most studies found slight increases in high-density lipoprotein (HDL) cholesterol but few have provided evidence on HDL functionality with disappointing results. However, there is broad agreement that these drugs provide cardiovascular protection through several mechanisms. Our group demonstrated that dapagliflozin improves myocardial flow reserve (MFR) in patients with type 2 diabetes (T2D) with coronary artery disease (CAD). The underlying mechanisms are still unknown, although in vitro studies have suggested the involvement of nitric oxide (NO).

AIM

To investigate changes in HDL-mediated modulation of NO production with dapagliflozin and whether there is an association with MFR.

METHODS

Sixteen patients with CAD-T2D were enrolled and randomized 1:1 to dapagliflozin or placebo for 4 weeks. Blood samples were collected before and after treatment for each group. The ability of HDL to stimulate NO production in endothelial cells was tested in vitro by incubating human umbilical vein endothelial cells (HUVEC) with apoB-depleted (apoB-D) serum of these patients. The production of NO was assessed by fluorescent assay, and results were expressed as fold versus untreated cells.

RESULTS

Change in HDL-mediated NO production remained similar in dapagliflozin and placebo group, even after adjustment for confounders. There were no significant correlations between HDL-mediated NO production and MFR either at baseline or after treatment. No changes were found in HDL cholesterol in either group, while low-density lipoprotein cholesterol (LDL cholesterol) significantly decreased compared to baseline only in treatment group (p = 0.043).

CONCLUSIONS

In patients with T2D-CAD, beneficial effects of dapagliflozin on coronary microcirculation seem to be unrelated to HDL functions. However, HDL capacity to stimulate NO production is not impaired at baseline; thus, the effect of drug treatments would be negligible. To conclude, we can assume that HDL-independent molecular pathways are involved in the improvement of MFR in this population.

TRIAL REGISTRATION

EudraCT No. 2016-003614-27; ClinicalTrials.gov Identifier: NCT03313752.

The Association Between Lipid Profile and Subfoveal Choroidal Thickness in Chinese Patients with Proliferative Diabetic Retinopathy Secondary to Type 2 Diabetes

Introduction

Extensive studies have studied the factors associated with subfoveal choroidal thickness (SFCT). However, studies of the association between lipid profile and SFCT in patients with proliferative diabetic retinopathy (PDR) in type 2 diabetes remain limited. Thus, we aimed to investigate the relationship between lipid profile and SFCT in patients with PDR.

Materials and Methods

This was a retrospective cross-sectional study. The included participants were inpatients who underwent vitrectomy for PDR with type 2 diabetes and contralateral eyes of PDR patients meeting the criteria. Multivariate linear regression analysis was used to determine the independent association between lipid profile and SFCT.

Results

A total of 131 participants with PDR were enrolled in the final analysis. The average age of the participants was 55.76 ± 9.88 years, and the average SFCT was 276.10 ± 92.92 μm. Multivariate linear regression model results showed that in the fully adjusted model, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) had a negative association with SFCT (β = -16.51, 95% CI: -29.57, -3.46; P = 0.0148; β = -42.65, 95% CI: -82.60, -2.70; P = 0.0390; β = -17.89, 95% CI: -33.24, -2.54; P = 0.0245, respectively), while triglyceride was not significantly associated with SFCT (β = 5.23, 95% CI: -18.57, 29.02; P = 0.6678). Furthermore, the results of stratified analysis showed that except for triglyceride, the trends of total cholesterol, HDL-C, LDL-C, and SFCT were consistent among different stratifications in participants.

Conclusion

The cholesterol profile had a significant negative association with SFCT in Chinese PDR patients, but triglyceride was not significantly associated with SFCT. This suggests that these systemic imbalances contribute to choroidal changes, and often coexist in diabetic patients.

Effects of cholesterol-lowering probiotics on non-alcoholic fatty liver disease in FXR gene knockout mice

Background/aims

Some studies showed that probiotics could improve the composition and structure of gut microbiota. Changes in the gut microbiota may alter bile acid (BAs) composition and kinetics, improving non-alcoholic fatty liver disease (NAFLD). However, it still needs to be clarified how probiotics improve both the metabolism of BAs and NAFLD. This study aimed to reveal the regulatory mechanisms of cholesterol-lowering (CL) probiotics on NAFLD from aspects involved in BA metabolism in FXR gene knockout (FXR-/-) mice.

Methods

FXR-/- male mice were randomly divided into three groups based on different interventions for 16 weeks, including normal diet (ND), high-fat diet (HFD), and probiotic intervention in the HFD (HFD+P) group. 16s rDNA sequencing and ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) were utilized to analyze the changes in gut microbiota and fecal bile acids in mice.

Results

We found that the intervention of the CL probiotics improved liver lipid deposition and function in HFD-induced NAFLD mice by decreasing the levels of total cholesterol (TC; p = 0.002) and triglyceride (TG; p = 0.001) in serum, as well as suppressing liver inflammation, such as interleukin-1 beta (IL-1β; p = 0.002) and tumor necrosis factor-alpha (TNF-α; p < 0.0001). 16S rDNA sequencing and metabolomic analyses showed that probiotics effectively reduced the abundance of harmful gut microbiota, such as Firmicutes (p = 0.005), while concomitantly increasing the abundance of beneficial gut microbiota in NAFLD mice, such as Actinobacteriota (p = 0.378), to improve NAFLD. Compared with the ND group, consuming an HFD elevated the levels of total BAs (p = 0.0002), primary BAs (p = 0.017), and secondary BAs (p = 0.0001) in mice feces, while the intervention with probiotics significantly reduced the increase in the levels of fecal total bile acids (p = 0.013) and secondary bile acids (p = 0.017) induced by HFD.

Conclusion

The CL probiotics were found to improve liver function, restore microbiota balance, correct an abnormal change in the composition and content of fecal bile acids, and repair the damaged intestinal mucosal barrier in mice with NAFLD, ultimately ameliorating the condition. These results suggested that CL probiotics may be a promising and health-friendly treatment option for NAFLD.

HDL and chronic kidney disease

Low HDL-cholesterol (HDL-C) concentrations are a typical trait of the dyslipidemia associated with chronic kidney disease (CKD). In this condition, plasma HDLs are characterized by alterations in structure and function, and these particles can lose their atheroprotective functions, e.g., the ability to promote cholesterol efflux from peripheral cells, anti-oxidant and anti-inflammatory proprieties and they can even become dysfunctional, i.e., exactly damaging. The reduction in plasma HDL-C levels appears to be the only lipid alteration clearly linked to the progression of renal disease in CKD patients. The association between the HDL system and CKD development and progression is also supported by the presence of genetic kidney alterations linked to HDL metabolism, including mutations in the APOA1, APOE, APOL and LCAT genes. Among these, renal disease associated with LCAT deficiency is well characterized and lipid abnormalities detected in LCAT deficiency carriers mirror the ones observed in CKD patients, being present also in acquired LCAT deficiency. This review summarizes the major alterations in HDL structure and function in CKD and how genetic alterations in HDL metabolism can be linked to kidney dysfunction. Finally, the possibility of targeting the HDL system as possible strategy to slow CKD progression is reviewed.

SFRP4 Reduces Atherosclerosis Plaque Formation in ApoE Deficient Mice

Secreted frizzled related protein 4 (SFRP4), a member of the SFRPs family, contributes to a significant function in metabolic and cardiovascular diseases. However, there is not enough evidence to prove the antiatherosclerosis effect of SFRP4 in ApoE knock-out (KO) mice. ApoE KO mice were fed a western diet and injected adenovirus (Ad)-SFRP4 through the tail vein for 12 weeks. Contrasted with the control cohort, the area of atherosclerotic plaque in ApoE KO mice overexpressing SFRP4 was reduced significantly. Plasma high-density lipoprotein cholesterol was elevated in the Ad-SFRP4 group. RNA sequence analysis indicated that there were 96 differentially expressed genes enriched in 10 signaling pathways in the mRNA profile of aortic atherosclerosis lesions. The analysis data also revealed the expression of a number of genes linked to metabolism, organism system, and human disease. In summary, our data demonstrates that SFRP4 could play an important role in improving atherosclerotic plaque formation in the aorta.

Association of Neutrophil to High-Density Lipoprotein Cholesterol Ratio with Cardiac Ultrasound Parameters and Cardiovascular Risk: A Cross-Sectional Study Based on Healthy Populations

Background

Neutrophils and high-density lipoprotein cholesterol (HDL-C) are significantly linked to cardiovascular disease (CVD). This study investigates the correlation of neutrophil count to HDL-C ratio (NHR) with cardiac ultrasound parameters and cardiovascular risk in healthy populations.

Materials and Methods

Firstly, NHR was calculated based on neutrophils and HDL-C. Then, the differences in basic clinical characteristics and cardiac ultrasound parameters were compared between the high and low NHR groups, males and females. Subsequently, cardiovascular risk was predicted according to the Chinese 10-year ischemic cardiovascular disease (ICVD) risk assessment tool for people aged 35-60 years. Finally, the correlation between NHR and cardiac ultrasound parameters and cardiovascular risk was calculated.

Results

A total of 3020 healthy participants, 1879 males and 1141 females, were included. Participants in the high NHR group had significantly increased Aorta (AO), Left Atrium (LA), Right Atrium (RA), Right Ventricle (RV), End Systolic Diameter of Left Ventricle (ESD), End Diastolic Diameter of Left Ventricle (EDD), Main Pulmonary Artery (MPA), Right Ventricular Outflow Tract (RVOT), Interventricular Septum (IVS), Left Ventricular Posterior Wall (LVPW), and cardiovascular risk and decreased E/A values compared to those in the low NHR group. The same results were found in males participants compared to females. A total of 1670 participants underwent ICVD risk assessment tool. Cardiovascular risk was significantly higher in those with high NHR and in males than in those with low NHR and in females. Correlation analysis showed that NHR was positively correlated with AO, LA, RA, RV, ESD, EDD, MPA, RVOT, IVS, LVPW and cardiovascular risk, and negatively correlated with E/A values.

Conclusion

Our study demonstrates that NHR is significantly associated with cardiac ultrasound parameters and cardiovascular risk in healthy populations. NHR may serve as a useful indicator for the early diagnosis and treatment of cardiovascular disease among healthy populations.

Air Pollution: Another Threat to HDL Function

Epidemiological studies have consistently demonstrated a positive association between exposure to air pollutants and the incidence of cardiovascular disease, with the strongest evidence for particles with a diameter < 2.5 μm (PM2.5). Therefore, air pollution has been included among the modifiable risk factor for cardiovascular outcomes as cardiovascular mortality, acute coronary syndrome, stroke, heart failure, and arrhythmias. Interestingly, the adverse effects of air pollution are more pronounced at higher levels of exposure but were also shown in countries with low levels of air pollution, indicating no apparent safe threshold. It is generally believed that exposure to air pollution in the long-term can accelerate atherosclerosis progression by promoting dyslipidemia, hypertension, and other metabolic disorders due to systemic inflammation and oxidative stress. Regarding high density lipoproteins (HDL), the impact of air pollution on plasma HDL-cholesterol levels is still debated, but there is accumulating evidence that HDL function can be impaired. In particular, the exposure to air pollution has been variably associated with a reduction in their cholesterol efflux capacity, antioxidant and anti-inflammatory potential, and ability to promote the release of nitric oxide. Further studies are needed to fully address the impact of various air pollutants on HDL functions and to elucidate the mechanisms responsible for HDL dysfunction.

Associations between myeloperoxidase and paraoxonase-1 and type 2 diabetes in patients with ischemic heart disease

BACKGROUND

The phrase "dysfunctional high-density lipoprotein" has been developed in the literature to describe the particle which loses its basic role- anti-oxidative and anti-inflammatory activity. In this porcess, the significance of enzymes- pro-oxidant myeloperoxidase (MPO) and antioxidant paraoxonase-1 (PON-1) from the perspective of HDL-C function has been noted.

AIMS

The objective of this study was to analyze the associations between two enzymes -MPO and PON-1 and type 2 diabetes (T2DM) in patients with ischemic heart disease (IHD).

METHODS

An observational cross-sectional study including 70 patients with IHD of whom 35 had also T2DM, and 35 had no T2DM. Laboratory tests (MPO, PON-1, fasting glucose, glycated hemoglobin, total cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, and high-sensitivity C-reactive protein) were performed.

RESULTS

The study revealed a significant difference in the serum concentration of the enzymes between patients with IHD with and without T2DM. Our results showed increased MPO concentration levels in diabetic patients. The analysis also revealed that T2DM is independently associated with an increase in MPO levels. Simultaneously, a decrease in PON-1 levels was observed in patients with T2DM. The study also revealed that T2DM is independently associated with a decrease in PON-1 levels.

CONCLUSIONS

In patients with type 2 diabetes the profile of enzymes involved in high-density lipoprotein metabolism in patients with IHD is worse than in patients without T2DM. The increase in the levels of MPO, an enzyme with oxidative and atherogenic properties and on a decrease in PON-1 levels, an enzyme with antioxidant and atheroprotective properties is observed.

Body Mass Index Modulates the Impact of Short-Term Exposure to Air Particulate Matter on High-Density Lipoprotein Function

Air particulate matter (PM) exposure has been associated with increased cardiovascular risk, especially in obesity. By triggering inflammation and oxidative stress, PM could impact atheroprotection by high-density lipoproteins (HDL). The aim of the study was to assess the relationship between short-term exposure to PM and HDL function, and the modifying effect of body mass index (BMI). Daily exposures to PM10 and PM2.5 of 50 subjects with overweight/obesity and 41 healthy volunteers with BMI < 30 kg/m2 were obtained from fixed monitoring stations. HDL function was assessed as promotion of nitric oxide (NO) release by endothelial cells and reduction in cholesterol in macrophages. HDL-induced NO release progressively declined with the increase in BMI. No association was found between HDL function and PM exposure, but a modifying effect of BMI was observed. The positive association between PM10 exposure at day −1 and NO production found at normal BMI values was lost in participants with higher BMI. Similar results were obtained for the reduction in macrophage cholesterol. The loss of the compensatory response of HDL function to PM exposure at increasing BMI levels could contribute to the endothelial dysfunction induced by PM and help to explain the susceptibility of subjects with obesity to air pollution.

HDL-mediated reduction of cholesterol content inhibits the proliferation of prostate cancer cells induced by LDL: Role of ABCA1 and proteasome inhibition

High-density lipoproteins (HDL) are well known for their atheroprotective function, mainly due to their ability to remove cell cholesterol and to exert antioxidant and anti-inflammatory activities. Through the same mechanisms HDL could also affect the development and progression of tumors. Cancer cells need cholesterol to proliferate, especially in hormone-dependent tumors, as prostate cancer (PCa). Aim of the study was to investigate the ability of HDL to modulate cholesterol content and metabolism in androgen receptor (AR)-positive and AR-null PCa cell lines and the consequences on cell proliferation. HDL inhibited colony formation of LNCaP and PC3 cells. HDL reduced cell cholesterol content and proliferation of LNCaP cells loaded with low-density lipoproteins but were not effective on PC3 cells. Here, the expression of the ATP-binding cassette transporter A1 (ABCA1) was markedly reduced due to proteasome degradation. Bortezomib, a proteasome inhibitor, restored ABCA1 expression and HDL ability to promote cholesterol removal from PC3; consequently, HDL inhibited the proliferation of PC3 cells induced by LDL only after bortezomib pre-treatment. In conclusion, the antiproliferative activity of HDL on AR-positive and AR-null PCa cells also rely on cholesterol removal, a process in which the ABCA1 transporter plays a key role.

LCAT- targeted therapies: Progress, failures and future

Lecithin: cholesterol acyltransferase (LCAT) is the only enzyme in plasma which is able to esterify cholesterol and boost cholesterol esterify with phospholipid-derived acyl chains. In order to better understand the progress of LCAT research, it is always inescapable that it is linked to high-density lipoprotein (HDL) metabolism and reverse cholesterol transport (RCT). Because LCAT plays a central role in HDL metabolism and RCT, many animal studies and clinical studies are currently aimed at improving plasma lipid metabolism by increasing LCAT activity in order to find better treatment options for familial LCAT deficiency (FLD), fish eye disease (FED), and cardiovascular disease. Recombinant human LCAT (rhLCAT) injections, cells and gene therapy, and small molecule activators have been carried out with promising results. Recently rhLCAT therapies have entered clinical phase II trials with good prospects. In this review, we discuss the diseases associated with LCAT and therapies that use LCAT as a target hoping to find out whether LCAT can be an effective therapeutic target for coronary heart disease and atherosclerosis. Also, probing the mechanism of action of LCAT may help better understand the heterogeneity of HDL and the action mechanism of dynamic lipoprotein particles.

High-density lipoproteins: A promising tool against cancer

High-density lipoproteins (HDL) are well known for their protective role against the development and progression of atherosclerosis. Atheroprotection is mainly due to the key role of HDL within the reverse cholesterol transport, and to their ability to exert a series of antioxidant and anti-inflammatory activities. Through the same mechanisms HDL could also affect cancer cell proliferation and tumor progression. Many types of cancers share common alterations of cellular metabolism, including lipid metabolism. In this context, not only fatty acids but also cholesterol and its metabolites play a key role. HDL were shown to reduce cancer cell content of cholesterol, overall rewiring cholesterol homeostasis. In addition, HDL reduce oxidative stress and the levels of pro-inflammatory molecules in cancer cells and in the tumor microenvironment (TME). Here, HDL can also help in reverting tumor immune escape and in inhibiting angiogenesis. Interestingly, HDL are good candidates for drug delivery, targeting antineoplastic agents to the tumor mass mainly through their binding to the scavenger receptor BI. Since they could affect cancer development and progression per se, HDL-based drug delivery systems may render cancer cells more sensitive to antitumor agents and reduce the development of drug resistance.

Association between extremely high high-density lipoprotein-cholesterol and hypertensive retinopathy: results of a cross-sectional study from Kanagawa Investigation of Total Checkup Data from the National Database-6 (KITCHEN-6)

OBJECTIVES

Doubt has been cast on the atheroprotective effect of very high high-density lipoprotein cholesterol (HDL-C). Hypertensive retinopathy (HR) is caused by persistent systemic hypertension. Therefore, we aimed to investigate the association between extremely high HDL-C (EH-HDL) and HR.

DESIGN

A cross-sectional study.

PARTICIPANTS

A total of 4072 general Japanese population aged 40-74 years who underwent regular medical check-ups including fundus examinations.

OUTCOME MEASURES

HR and clinical parameters including serum HDL-C were investigated. HR was determined by the Keith-Wagener classification and the Scheie classifications for Hypertension and Atherosclerosis (n=4054 available). Serum HDL-C was divided into five categories: 30-49, 50-69, 70-89, 90-109 and ≥110 mg/dL.

RESULTS

Overall, 828 (20.3%) subjects had Keith-Wagener-HR, 578 (14.3%) had hypertension-HR, and 628 (15.5%) had atherosclerosis-HR. Blood pressure decreased as HDL-C level increased, whereas the prevalences of HRs showed U-shaped curves against HDL-C with minimum values for HDL-C 90-109 mg/dL. In logistic regression analyses, EH-HDL ≥110 mg/dL was significantly associated with Keith-Wagener-HR and atherosclerosis-HR, compared with HDL-C 90-109 mg/dL after adjustments for age, sex and systolic blood pressure (OR 3.01, 95% CI 1.45 to 6.27 and OR 2.23, 95% CI 1.03 to 4.86). The hypertension-HR was not significantly associated with EH-HDL regardless of adjustment for the confounding factors (p=0.05-0.08). Although serum HDL-C as a continuous variable was inversely associated with three HRs, which disappeared after adjustment for the confounding factors.

CONCLUSION

EH-HDL may be associated with HR independently of blood pressure, suggesting that EH-HDL reflects a special atherosclerotic condition.

High-Density Lipoproteins and the Kidney

Dyslipidemia is a typical trait of patients with chronic kidney disease (CKD) and it is typically characterized by reduced high-density lipoprotein (HDL)-cholesterol(c) levels. The low HDL-c concentration is the only lipid alteration associated with the progression of renal disease in mild-to-moderate CKD patients. Plasma HDL levels are not only reduced but also characterized by alterations in composition and structure, which are responsible for the loss of atheroprotective functions, like the ability to promote cholesterol efflux from peripheral cells and antioxidant and anti-inflammatory proprieties. The interconnection between HDL and renal function is confirmed by the fact that genetic HDL defects can lead to kidney disease; in fact, mutations in apoA-I, apoE, apoL, and lecithin–cholesterol acyltransferase (LCAT) are associated with the development of renal damage. Genetic LCAT deficiency is the most emblematic case and represents a unique tool to evaluate the impact of alterations in the HDL system on the progression of renal disease. Lipid abnormalities detected in LCAT-deficient carriers mirror the ones observed in CKD patients, which indeed present an acquired LCAT deficiency. In this context, circulating LCAT levels predict CKD progression in individuals at early stages of renal dysfunction and in the general population. This review summarizes the main alterations of HDL in CKD, focusing on the latest update of acquired and genetic LCAT defects associated with the progression of renal disease.

Metabolically healthy obesity is associated with longitudinal changes in high-density lipoprotein cholesterol in Chinese adults

PURPOSE

Whether metabolically healthy obesity (MHO) is associated with longitudinal changes in high-density lipoprotein cholesterol (HDL-C) remains unclear.

METHODS

MHO was defined as participants with overweight and obesity (BMI ≥ 24.0 kg/m², n = 2921), free of history of metabolic diseases, and without abnormalities of blood pressure, fasting blood glucose, hemoglobin A1c, lipid profile, carotid artery and liver ultrasonographic findings at baseline. Metabolically healthy normal weight (MHN) was defined as participants with normal weight (BMI < 24.0 kg/m², n = 9578) and without above-mentioned abnormalities. HDL-C, fasting blood glucose, hemoglobin A1c, and blood pressure were assessed annually. Glucose abnormality was considered if either FBG ≥ 5.6 mmol/L or HbA1c ≥ 5.7%; while, high blood pressure (HBP) was considered if either systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 80 mmHg during 5 years of follow-up.

RESULTS

Compared with the MHN group, the adjusted mean difference in HDL-C change rate was - 0.005 mmol/L per year [95% confidence interval (CI) - 0.007, - 0.003] for MHO after adjustment for a series of potential confounders. Furthermore, transiting to abnormality of blood glucose, but not high blood pressure, was associated with lower cumulative average of HDL-C in MHN group, compared with those remained in metabolically healthy status.

CONCLUSIONS

MHO and transiting from metabolically healthy to abnormality of blood glucose were associated with HDL-C in Chinese adults.

LEVEL OF EVIDENCE

III, cohort study.

Metabolomic analysis of plasma from normal-weight adults with hypo-HDL cholesterolemia by UPLC-QTOF MS

High-density lipoprotein cholesterol (HDL-C) is negatively correlated with atherosclerotic cardiovascular disease. The prevalence of hypo-HDL cholesterolemia is as high as 33.9%. The plasma metabolomic differences between hypo-HDL cholesterolemia populations and normal controls were investigated using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Participants with hypo-HDL cholesterolemia and normal controls were clearly discriminated from each other on the orthogonal partial least squares-discriminant analysis score plot and a total of 90 differential metabolites were identified, including down-regulated phosphatidylserine [18:0/20:3(8Z,11Z,14Z)], phosphatidylcholine [19:0/18:3(6Z,9Z,12Z)], phosphatidylserine, phosphatidylethanolamine [18:0/20:4(5Z,8Z,11Z,13E) (15Ke)], etc., and up-regulated triglyceride [15:0/18:1(9Z)/18:3(9Z,12Z,15Z)][iso6], 13-methyl-1-tritriacontene, tridodecylamine, etc. Most of the changed metabolites were lipids, notably, a significant part of which were odd chain fatty acid incorporated lipids. Carnitine shuttle was the most significant metabolic pathway, except for the disturbed glycerophospholipid metabolism, glycosphingolipid metabolism and sphingolipid metabolism in participants with hypo-HDL cholesterolemia. We identified the key metabolites and metabolic pathways that may be changed in hypo-HDL cholesterolemia participants, providing useful clues for studying the metabolic mechanisms and for early prevention of hypo-HDL cholesterolemia and dyslipidemia.

Connection between the Altered HDL Antioxidant and Anti-Inflammatory Properties and the Risk to Develop Alzheimer's Disease: A Narrative Review

The protein composition of high-density lipoprotein (HDL) is extremely fluid. The quantity and quality of protein constituents drive the multiple biological functions of these lipoproteins, which include the ability to contrast atherogenesis, sustained inflammation, and toxic effects of reactive species. Several diseases where inflammation and oxidative stress participate in the pathogenetic process are characterized by perturbation in the HDL proteome. This change inevitably affects the functionality of the lipoprotein. An enlightening example in this frame comes from the literature on Alzheimer's disease (AD). Growing lines of epidemiological evidence suggest that loss of HDL-associated proteins, such as lipoprotein phospholipase A2 (Lp-PLA2), glutathione peroxidase-3 (GPx-3), and paraoxonase-1 and paraoxonase-3 (PON1, PON3), may be a feature of AD, even at the early stage. Moreover, the decrease in these enzymes with antioxidant/defensive action appears to be accompanied by a parallel increase of prooxidant and proinflammatory mediators, in particular myeloperoxidase (MPO) and serum amyloid A (SAA). This type of derangement of balance between two opposite forces makes HDL dysfunctional, i.e., unable to exert its “natural” vasculoprotective property. In this review, we summarized and critically analyzed the most significant findings linking HDL accessory proteins and AD. We also discuss the most convincing hypothesis explaining the mechanism by which an observed systemic occurrence may have repercussions in the brain.

Monocyte to high-density lipoprotein ratio and cardiovascular events in patients on peritoneal dialysis

BACKGROUND AND AIMS

The monocyte to high-density lipoprotein cholesterol ratio (MHR) is associated with multiple cardiovascular diseases. However, the role of the MHR in predicting cardiovascular diseases in patients on peritoneal dialysis remains unclear.

METHODS AND RESULTS

Eight hundred and eighty incident peritoneal dialysis patients were enrolled from November 1, 2005, to February 28, 2017, and followed until May 31, 2017. Primary outcomes were cardiovascular events. Using the X-tile program, these patients were divided into three groups according to the MHR. Kaplan-Meier method and Cox regressions were used for survival analysis. During a median follow-up period of 26 months (interquartile range: 12-39 months), 139 cardiovascular events were recorded. After multiple adjustment, the high MHR group was associated with a 1.97-fold increase in the cardiovascular events hazard compared to that of the low group in the overall population (hazard ratio: 1.97; 95% CI, 1.19-3.28; P = 0.009). Subgroup analysis demonstrated that the association between the MHR and a higher risk of cardiovascular events was strongest in the subgroup of patients with diabetes (P for interaction = 0.004). In this subgroup, the high MHR group was found to be associated with a higher risk of cardiovascular events compared to the low group (hazard ratio: 7.69; 95% CI, 2.76-21.47).

CONCLUSION

This study suggests that the MHR is independently associated with the risk of cardiovascular events in patients undergoing peritoneal dialysis, and diabetes status can influence the association between the MHR and the risk of cardiovascular events.

Role of Lipoproteins in the Microenvironment of Hormone-Dependent Cancers

The tumor microenvironment (TME) is an attractive target to develop novel strategies for hormone-dependent cancers. Several molecules in the TME can favor tumor development and progression, including lipoproteins. Lipoproteins are taken up by cancer cells, providing them with cholesterol and fatty acids. Cholesterol regulates cell signaling and it is converted into a series of bioactive metabolites, including hormones. The conflicting results of epidemiological and interventional studies suggest that the local availability of lipoproteins in the TME is more relevant for cancer biology than their circulating levels. Thus, reducing lipoprotein uptake and stimulating cell cholesterol efflux to high-density lipoproteins (HDLs) can represent a novel adjuvant strategy for cancer management. HDL-like particles can also act as drug delivery systems for tumor targeting.

Associations Between Apolipoprotein A1, High-Density Lipoprotein Cholesterol, and Urinary Cytokine Levels in Elderly Males and Females

There exists a close relationship between cardiovascular diseases and chronic kidney disease. Apolipoprotein A1 and high-density lipoprotein (HDL) cholesterol are widely used as cardiovascular risk markers but they also have anti-inflammatory properties. The aim of this study was to investigate any associations between HDL levels and cytokine levels in urine. We randomly selected 90 urine samples from the Prospective Investigation of the Vasculature in Uppsala Seniors Study (41 males and 49 females). The samples were analyzed with 2 multiplex assays, Multiplex Inflammation I and Cardiovascular II kits (Olink Bioscience, Uppsala, Sweden). We analyzed the correlations between 158 cytokines in urine with apolipoprotein A1, HDL cholesterol, apolipoprotein B, and low-density lipoprotein cholesterol. There were strong correlations for apolipoprotein A1 and HDL cholesterol with individual cytokines. After adjustment for multiplicity testing, there were 33 significant correlations between apolipoprotein A1 and cytokine levels and 14 of these were also significantly correlated with HDL cholesterol. The strongest associations were observed for IL-1α, SPON2, RAGE, PAR-1, TRAIL-R2, IL-4RA, TNFRSF11A, and SCF. A total of 28 out of 33 correlations were negative, indicating a negative relationship between apolipoprotein A1 and urinary cytokines. The study shows a negative correlation between apolipoprotein A1 and HDL cholesterol and urinary cytokine levels. The finding is in agreement with the anti-inflammatory properties of HDL.

Plaque Calcification

Vascular calcification (VC) is strongly associated with all-cause mortality and is an independent predictor of cardiovascular events. Resulting from its complex, multifaceted nature, targeted treatments for VC have not yet been developed. Lipoproteins are well characterized in the pathogenesis of atherosclerotic plaques, leading to the development of plaque regressing therapeutics. Although their roles in plaque progression are well documented, their roles in VC, and calcification of a plaque, are not well understood. In this review, early in vitro data and clinical correlations suggest an inhibitory role for HDL (high-density lipoproteins) in VC, a stimulatory role for LDL (low-density lipoprotein) and VLDL (very low-density lipoprotein) and a potentially causal role for Lp(a) (lipoprotein [a]). Additionally, after treatment with a statin or PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor, plaque calcification is observed to increase. With the notion that differing morphologies of plaque calcification associate with either a more stable or unstable plaque phenotype, uncovering the mechanisms of lipoprotein-artery wall interactions could produce targeted therapeutic options for VC.

The future of apolipoprotein E mimetic peptides in the prevention of cardiovascular disease

PURPOSE OF REVIEW

This review aims to discuss the recent developments in the area of apolipoprotein E (apoE) mimetics and their therapeutic potential for treating cardiovascular disease, the leading cause of mortality worldwide.

RECENT FINDINGS

Ongoing research efforts target the development of novel therapies that would not only reduce circulating levels of atherogenic lipoproteins, but could also increase high density lipoprotein cholesterol (HDL-C) levels and/or improve HDL function. Among them, synthetic peptides that mimic the structure of natural human apoE, a component of triglyceride-rich lipoproteins and HDL, have been designed and proven to be functionally similar to apoE. In specific, apoE mimetic peptides mediate hepatic clearance of circulating atherogenic lipoproteins, dramatically reduce plasma cholesterol, and lead to attenuation of atherosclerosis development in vivo. These peptides also exhibit pleiotropic antiatherogenic properties, such as macrophage cholesterol efflux capacity, as well as anti-inflammatory and antioxidative functions.

SUMMARY

ApoE mimetics are undergoing preclinical and clinical evaluation with promising results to date that render them attractive candidates in cardiovascular disease prevention and treatment.

Lipids: a personal view of the past decade

The past decade has witnessed considerable progress in the field of lipids. New drugs have been "rapidly" developed and some of these drugs have already been evaluated in event-based large trials. This evidence has led to the guidelines recommending new, more aggressive treatment goals for low-density lipoprotein cholesterol (LDL-C) levels. Although LDL-C remains the principal goal for cardiovascular disease (CVD) risk reduction, there has also been considerable interest in other lipid variables, such as high-density lipoprotein cholesterol, triglycerides, and lipoprotein(a). Statin intolerance is now considered a very important topic in daily clinical practice. This has resulted in more attention focusing on non-statin drugs [e.g., ezetimibe and proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors] and statin-related side effects. The latter mainly involve muscles, but there is also a need to consider other adverse effects associated with statin use (e.g., new onset diabetes). New specific areas of statin use have attracted interest. For example, statin-loading before procedures (e.g., coronary stenting), the prevention of stroke, and the treatment of non-alcoholic fatty liver disease (NAFLD). Statins will remain the most widely used drugs to treat dyslipidaemia and decrease CVD risk. However, we also need to briefly consider some other lipid-lowering drugs, including those that may become available in the future.

Current and Emerging Reconstituted HDL-apoA-I and HDL-apoE Approaches to Treat Atherosclerosis

Atherosclerosis affects millions of people worldwide. However, the wide variety of limitations in the current therapeutic options leaves much to be desired in future lipid-lowering therapies. For example, although statins, which are the first-line treatment for coronary heart disease (CHD), reduce the risk of cardiovascular events in a large percentage of patients, they lead to optimal levels of low density lipoprotein-cholesterol (LDL-C) in only about one-third of patients. A new promising research direction against atherosclerosis aims to improve lipoprotein metabolism. Novel therapeutic approaches are being developed to increase the levels of functional high density lipoprotein (HDL) particles. This review aims to highlight the atheroprotective potential of the in vitro synthesized reconstituted HDL particles containing apolipoprotein E (apoE) as their sole apolipoprotein component (rHDL-apoE). For this purpose, we provide: (1) a summary of the atheroprotective properties of native plasma HDL and its apolipoprotein components, apolipoprotein A-I (apoA-I) and apoE; (2) an overview of the anti-atherogenic functions of rHDL-apoA-I and apoA-I-containing HDL, i.e., natural HDL isolated from transgenic Apoa1^−/− × Apoe^−/− mice overexpressing human apoA-I (HDL-apoA-I); and (3) the latest developments and therapeutic potential of HDL-apoE and rHDL-apoE. Novel rHDL formulations containing apoE could possibly present enhanced biological functions, leading to improved therapeutic efficacy against atherosclerosis.

Attenuation of atherogenic apo B-48-dependent hyperlipidemia and high density lipoprotein remodeling induced by vitamin C and E combination and their beneficial effect on lethal ischemic heart disease in mice

Background and aims

Atherosclerotic cardiovascular disease is highly prevalent and its underlying pathogenesis involves dyslipidemia including pro-atherogenic high density lipoprotein (HDL) remodeling. Vitamins C and E have been proposed as atheroprotective agents for cardiovascular disease management. However, their effects and benefits on high density lipoprotein function and remodeling are unknown. In this study, we evaluated the role of vitamin C and E on non HDL lipoproteins as well as HDL function and remodeling, along with their effects on inflammation/oxidation biomarkers and atherosclerosis in atherogenic diet-fed SR-B1 KO/ApoER61^h/h mice.

Methods and results

Mice were pre-treated for 5 weeks before and during atherogenic diet feeding with vitamin C and E added to water and diet, respectively. Compared to a control group, combined vitamin C and E administration reduced serum total cholesterol and triglyceride levels by decreasing apo B-48-containing lipoproteins, remodeled HDL particles by reducing phospholipid as well as increasing PON1 and apo D content, and diminished PLTP activity and levels. Vitamin supplementation improved HDL antioxidant function and lowered serum TNF-α levels. Vitamin C and E combination attenuated atherogenesis and increased lifespan in atherogenic diet-fed SR-B1 KO/ApoER61^h/h mice.

Conclusions

Vitamin C and E administration showed significant lipid metabolism regulating effects, including HDL remodeling and decreased levels of apoB-containing lipoproteins, in mice. In addition, this vitamin supplementation generated a cardioprotective effect in a murine model of severe and lethal atherosclerotic ischemic heart disease.