Dysfunctional high-density lipoproteins have distinct composition, diminished anti-inflammatory potential and discriminate acute coronary syndrome from stable coronary artery disease patients

Dysfunctional High-Density Lipoprotein Cholesterol and Coronary Artery Disease: A Narrative Review

High-density lipoprotein (HDL) cholesterol is traditionally viewed as protective against cardiovascular disease (CVD). However, emerging evidence reveals that dysfunctional HDL, characterized by impaired reverse cholesterol transport (RCT), reduced anti-inflammatory and antioxidant activities and increased endothelial dysfunction, which can contribute to coronary artery disease (CAD). Dysfunctional HDL, resulting from oxidative modifications of Apolipoprotein A-1 (Apo A-1) and enzyme inactivation, fails to effectively remove cholesterol from peripheral tissues and may promote inflammation and atherosclerosis. Genetic mutations affecting HDL metabolism further complicate its role in cardiovascular health. Studies have shown that conventional therapies aimed at raising HDL-C levels do not necessarily reduce cardiovascular events, highlighting the need for new approaches that improve HDL functionality. Therapeutic strategies such as Apo A-1 mimetic peptides, reconstituted HDL infusions, and drugs targeting specific HDL metabolic pathways are being explored. Additionally, weight loss, statin therapy, and niacin have shown potential in enhancing HDL function. The pathophysiology of dysfunctional HDL involves complex mechanisms, including oxidative stress, inflammation, and genetic mutations, which alter its structure and function, diminishing its cardioprotective effects. New functional assays, such as the cholesterol efflux capacity (CEC) and HDL inflammatory index, provide more accurate predictions of cardiovascular risk by assessing HDL quality rather than quantity. As research progresses, the focus is shifting towards therapeutic strategies that enhance HDL function and address the root causes of its dysfunction, offering a more effective approach to reducing cardiovascular risk and preventing CAD.

Established and potential cardiovascular risk factors in metabolic syndrome: Effect of bariatric surgery

PURPOSE OF REVIEW

The aim of this review was to provide an overview of the role of novel biomarkers in metabolic syndrome, their association with cardiovascular risk and the impact of bariatric surgery on these biomarkers.

RECENT FINDINGS

Metabolic syndrome encompasses an intricate network of health problems, and its constituents extend beyond the components of its operational definition. Obesity-related dyslipidaemia not only leads to quantitative changes in lipoprotein concentration but also alteration in qualitative composition of various lipoprotein subfractions, including HDL particles, rendering them proatherogenic. This is compounded by the concurrent existence of obstructive sleep apnoea (OSA) and nonalcoholic fatty liver disease (NAFLD), which pave the common pathway to inflammation and oxidative stress culminating in heightened atherosclerotic cardiovascular disease (ASCVD) risk. Bariatric surgery is an exceptional modality to reverse both conventional and less recognised aspects of metabolic syndrome. It reduces the burden of atherosclerosis by ameliorating the impact of obesity and its related complications (OSA, NAFLD) on quantitative and qualitative composition of lipoproteins, ultimately improving endothelial function and cardiovascular morbidity and mortality.

SUMMARY

Several novel biomarkers, which are not traditionally considered as components of metabolic syndrome play a crucial role in determining ASCVD risk in metabolic syndrome. Due to their independent association with ASCVD, it is imperative that these are addressed. Bariatric surgery is a widely recognized intervention to improve the conventional risk factors associated with metabolic syndrome; however, it also serves as an effective treatment to optimize novel biomarkers.

High-density lipoprotein dysfunction in carotid artery stenosis

Background: High density lipoprotein (HDL) is well established to have an athero-protective role under normal conditions; however, pro-inflammatory alteration of HDL proteins may transform the HDL particle into a dysfunctional molecule. Our aim was to investigate HDL dysfunction by measuring enzyme-based markers in carotid artery stenosis (CAS). Patients and methods: All participants underwent duplex ultrasound and 52 subjects diagnosed with CAS and 51 subjects who had no significant stenosis (as controls) were enrolled in this study. Serum lipid profiles and serum parameters associated with dysfunctional HDL including myeloperoxidase (MPO), paraoxonase 1 (PON1), arylesterase (ARE) activity, and lipid hydroperoxide (LOOH) levels were measured. Results: It was found that the patients with CAS had increased levels of MPO and LOOH while PON1 activity was decreased. There was no significant difference between the CAS and non-CAS groups in terms of HDL levels. MPO/PON1, MPO/ARE, and LOOH/PON1 ratios were significantly increased in the CAS group. MPO/PON1 and MPO/ARE ratios both demonstrated significant correlations with degree of stenosis (%). Conclusions: The MPO/PON1 and MPO/ARE ratios may be potential serum markers that can enable the monitoring of HDL functionality and the assessment of atherosclerotic disease risks. Additionally, monitoring the oxidative balance of lipids on HDL molecules by LOOH/PON1 ratio may have value in the early detection of pro-atherosclerotic transformation of the HDL particle.

Elevated Levels of Circulating lncRNAs LIPCAR and MALAT1 Predict an Unfavorable Outcome in Acute Coronary Syndrome Patients

Coronary artery disease (CAD) is a leading cause of mortality worldwide. In this study, we aimed to assess the potential of plasma long non-coding RNAs (lncRNAs) LIPCAR and MALAT1 and microRNAs (miRNAs) miR-142-3p and miR-155-5p to discriminate unstable CAD patients from stable ones. 23 stable angina (SA), 21 unstable angina (UA), and 50 ST-segment elevation myocardial infarction (STEMI) patients were enrolled; their plasma was collected. ncRNA plasma levels were evaluated using RT-qPCR. All measured ncRNA levels were significantly increased in UA patients' plasma compared to SA patients' plasma and in STEMI-with major adverse cardiovascular event (MACE) patients' plasma vs. STEMI-without MACE patients' plasma. ROC analysis showed that increased levels of LIPCAR and MALAT1 were associated with UA, and the prognostic model improved with the addition of miR-155-5p levels. The assessed lncRNAs discriminated between hyperglycemic (HG) and normoglycemic (NG) UA patients, and they were associated with MACE incidence in STEMI patients; this prediction was improved by the addition of miR-142-3p levels to the ROC multivariate model. We propose LIPCAR and MALAT1 as effective diagnostic markers for vulnerable CAD, their association with HG in UA patients, and as robust predictors for unfavorable evolution of STEMI patients.

HDL Subclasses and the Distribution of Paraoxonase-1 Activity in Patients with ST-Segment Elevation Acute Myocardial Infarction

The aim of this multicentric study was to assess the impacts of oxidative stress, inflammation, and the presence of small, dense, low-density lipoproteins (sdLDL) on the antioxidative function of high-density lipoprotein (HDL) subclasses and the distribution of paraoxonase-1 (PON1) activity within HDL in patients with ST-segment elevation acute myocardial infarction (STEMI). In 69 STEMI patients and 67 healthy control subjects, the lipoproteins' subclasses were separated using polyacrylamide gradient (3-31%) gel electrophoresis. The relative proportion of sdLDL and each HDL subclass was evaluated by measuring the areas under the peaks of densitometric scans. The distribution of the relative proportion of PON1 activity within the HDL subclasses (pPON1 within HDL) was estimated using the zymogram method. The STEMI patients had significantly lower proportions of HDL2a and HDL3a subclasses (p = 0.001 and p < 0.001, respectively) and lower pPON1 within HDL3b (p = 0.006), as well as higher proportions of HDL3b and HDL3c subclasses (p = 0.013 and p < 0.001, respectively) and higher pPON1 within HDL2 than the controls. Independent positive associations between sdLDL and pPON1 within HDL3a and between malondialdehyde (MDA) and pPON1 within HDL2b were shown in the STEMI group. The increased oxidative stress and increased proportion of sdLDL in STEMI are closely related to the compromised antioxidative function of small HDL3 particles and the altered pPON1 within HDL.

The Oxidized Lipoproteins In Vivo: Its Diversity and Behavior in the Human Circulation

A high concentration of low-density lipoproteins (LDLs) in circulation has been well-known as a major risk factor for cardiovascular diseases. The presence of oxidized LDLs (oxLDLs) in atherosclerotic lesions and circulation was demonstrated using anti-oxLDL monoclonal antibodies. The so-called “oxLDL hypothesis”, as a mechanism for atherosclerosis development, has been attracting attention for decades. However, the oxLDL has been considered a hypothetical particle since the oxLDL present in vivo has not been fully characterized. Several chemically modified LDLs have been proposed to mimic oxLDLs. Some of the subfractions of LDL, especially Lp(a) and electronegative LDL, have been characterized as oxLDL candidates as oxidized phospholipids that stimulate vascular cells. Oxidized high-density lipoprotein (oxHDL) and oxLDL were discovered immunologically in vivo. Recently, an oxLDL-oxHDL complex was found in human plasma, suggesting the involvement of HDLs in the oxidative modification of lipoproteins in vivo. In this review, we summarize our understanding of oxidized lipoproteins and propose a novel standpoint to understand the oxidized lipoproteins present in vivo.

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.

Alterations of HDL's to piHDL's Proteome in Patients with Chronic Inflammatory Diseases, and HDL-Targeted Therapies

Chronic inflammatory diseases, such as rheumatoid arthritis, steatohepatitis, periodontitis, chronic kidney disease, and others are associated with an increased risk of atherosclerotic cardiovascular disease, which persists even after accounting for traditional cardiac risk factors. The common factor linking these diseases to accelerated atherosclerosis is chronic systemic low-grade inflammation triggering changes in lipoprotein structure and metabolism. HDL, an independent marker of cardiovascular risk, is a lipoprotein particle with numerous important anti-atherogenic properties. Besides the essential role in reverse cholesterol transport, HDL possesses antioxidative, anti-inflammatory, antiapoptotic, and antithrombotic properties. Inflammation and inflammation-associated pathologies can cause modifications in HDL's proteome and lipidome, transforming HDL from atheroprotective into a pro-atherosclerotic lipoprotein. Therefore, a simple increase in HDL concentration in patients with inflammatory diseases has not led to the desired anti-atherogenic outcome. In this review, the functions of individual protein components of HDL, rendering them either anti-inflammatory or pro-inflammatory are described in detail. Alterations of HDL proteome (such as replacing atheroprotective proteins by pro-inflammatory proteins, or posttranslational modifications) in patients with chronic inflammatory diseases and their impact on cardiovascular health are discussed. Finally, molecular, and clinical aspects of HDL-targeted therapies, including those used in therapeutical practice, drugs in clinical trials, and experimental drugs are comprehensively summarised.

Mitochondrial DNA Together with miR-142-3p in Plasma Can Predict Unfavorable Outcomes in Patients after Acute Myocardial Infarction

Myocardial infarction is one of the leading causes of death worldwide, despite numerous efforts to find efficient prognostic biomarkers and treatment targets. In the present study, we aimed to assess the potential of six microRNAs known to be involved in cardiovascular diseases, cell-free DNA (cfDNA), and mitochondrial DNA (mtDNA) circulating in plasma to be used as prognostic tools for the occurrence of unfavorable outcomes such as major adverse cardiovascular events (MACE) after acute ST-segment elevation myocardial infarction (STEMI). Fifty STEMI patients were enrolled and monitored for 6 months for the occurrence of MACE. Plasma was collected at three time points: upon admission to hospital (T0), at discharge from hospital (T1), and 6 months post-STEMI (T6). Plasma levels of miR-223-3p, miR-142-3p, miR-155-5p, miR-486-5p, miR-125a-5p, and miR-146a-5p, as well as of cfDNA and mtDNA, were measured by RT-qPCR. Results showed that the levels of all measured miRNAs, as well as of cfDNA and mtDNA, were the most increased at T1, compared to the other two time points. In the plasma of STEMI patients with MACE compared to those without MACE, we determined increased levels of miRNAs, cfDNA, and mtDNA at T1. Hence, we used the levels of all measured parameters at T1 for further statistical analysis. Statistical analysis demonstrated that all six miRNAs and cfDNA plus mtDNA levels, respectively, were associated with MACE. The minimal statistical model that could predict MACE in STEMI patients was the combination of mtDNA and miR-142-3p levels, as evidenced by ROC analysis (AUC = 0.97, p < 0.001). In conclusion, the increased plasma levels of mtDNA, along with miR-142-3p, could be used to predict unfavorable outcomes in STEMI patients.

Antitumor Properties of a New Macrocyclic Tetranuclear Oxidovanadium(V) Complex with 3-Methoxysalicylidenvaline Ligand

A wide variety of metal-based compounds have been obtained and studied for their antitumor activity since the intensely used cytostatic drugs (e.g., cisplatin) failed to accomplish their expected pharmacological properties. Thus, we aimed to develop a new vanadium-based drug and assess its antitumor properties using the human hepatocarcinoma (HepG2) cell line. The compound was synthesized from vanadyl sulfate, DL-valine, and o-vanillin and was spectrally and structurally characterized (UV-Vis, IR, CD, and single-crystal/powder-XRD). Compound stability in biological media, cell uptake, and the interaction with albumin were assessed. The mechanisms of its antitumor activity were determined compared to cisplatin by performing cytotoxicity, oxidative and mitochondrial status, DNA fragmentation, β-Tubulin synthesis investigation, and cell cycle studies. Herein, we developed a macrocyclic tetranuclear oxidovanadium(V) compound, [(V^VO)(L)(CH₃O)]₄, having coordinated four Schiff base (H₂L) ligands, 3-methoxysalicylidenvaline. We showed that [(V^VO)(L)(CH₃O)]₄: (i) has pH-dependent stability in biological media, (ii) binds to albumin in a dose-dependent manner, (iii) is taken up by cells in a time-dependent way, (iv) has a higher capacity to induce cell death compared to cisplatin (IC₅₀ = 6 μM vs. 10 μM), by altering the oxidative and mitochondrial status in HepG2 cells. Unlike cisplatin, which blocks the cell cycle in the S-phase, the new vanadium-based compound arrests it in S and G2/M-phase, whereas no differences in the induction of DNA fragmentation and reduction of β-Tubulin synthesis between the two were determined. Thus, the [(V^VO)(L)(CH₃O)]₄ antitumor mechanism involved corroboration between the generation of oxidative species, mitochondrial dysfunction, degradation of DNA, cell cycle arrest in the S and G2/M-phase, and β-Tubulin synthesis reduction. Our studies demonstrate the potent antitumor activity of [(V^VO)(L)(CH₃O)]₄ and propose it as an attractive candidate for anticancer therapy.

Clusterin, paraoxonase 1, and myeloperoxidase alterations induce high-density lipoproteins dysfunction and contribute to peripheral artery disease; aggravation by type 2 diabetes mellitus

Peripheral artery disease (PAD) is an atherosclerotic disorder affecting arteries of the lower limbs, the major risk factors including dyslipidemia and diabetes mellitus (DM). We aimed to identify alterations of the proteins in high-density lipoproteins (HDL) associated with HDL dysfunction in PAD patients. HDL₂ and HDL₃ were isolated from plasma of PAD patients with/without DM (PAD-DM/PAD) and healthy subjects (N). Apolipoprotein AI (ApoAI), ApoAII, ApoCIII, clusterin (CLU), paraoxonase 1 (PON1), myeloperoxidase (MPO), and ceruloplasmin (CP) were measured in HDL₂ /HDL₃ and plasma. Oxidation and glycation of the analyzed proteins were assessed as malondialdehyde-protein adducts (MDA) and advanced glycation end-products (AGE), respectively. The anti-inflammatory effect of HDL₃ was estimated as its potential to reduce monocyte adhesion to tumor necrosis factor α-activated endothelial cells. We show that in PAD patients compared to N subjects: (i) HDL₂ presented increased levels of MDA-PON1, AGE-PON1, AGE-ApoAI, ApoAII, ApoCIII, and CP levels, and decreased PON1 levels; (ii) HDL₃ had increased levels of MDA- and AGE-CLU and -ApoAI, MDA-PON1, ApoCIII, CLU, MPO, CP, and reduced PON1 levels. All these alterations were exacerbated by DM. These changes were more pronounced in HDL₃ , which had reduced anti-inflammatory potential in PAD and became pro-inflammatory in PAD-DM. In PAD patients' plasma, CLU levels and MPO specific activity increased, while PON1 specific activity decreased. In conclusion, HDL function is altered in PAD patients due to multiple modifications of associated proteins that are aggravated by DM. Plasma CLU, MPO, and PON1 could constitute indicators of HDL dysfunction and contribute to risk stratification in PAD patients.

ApoA-I mimetics reduce systemic and gut inflammation in chronic treated HIV

Novel therapeutic strategies are needed to attenuate increased systemic and gut inflammation that contribute to morbidity and mortality in chronic HIV infection despite potent antiretroviral therapy (ART). The goal of this study is to use preclinical models of chronic treated HIV to determine whether the antioxidant and anti-inflammatory apoA-I mimetic peptides 6F and 4F attenuate systemic and gut inflammation in chronic HIV. We used two humanized murine models of HIV infection and gut explants from 10 uninfected and 10 HIV infected persons on potent ART, to determine the in vivo and ex vivo impact of apoA-I mimetics on systemic and intestinal inflammation in HIV. When compared to HIV infected humanized mice treated with ART alone, mice on oral apoA-I mimetic peptide 6F with ART had consistently reduced plasma and gut tissue cytokines (TNF-α, IL-6) and chemokines (CX3CL1) that are products of ADAM17 sheddase activity. Oral 6F attenuated gut protein levels of ADAM17 that were increased in HIV-1 infected mice on potent ART compared to uninfected mice. Adding oxidized lipoproteins and endotoxin (LPS) ex vivo to gut explants from HIV infected persons increased levels of ADAM17 in myeloid and intestinal cells, which increased TNF-α and CX3CL1. Both 4F and 6F attenuated these changes. Our preclinical data suggest that apoA-I mimetic peptides provide a novel therapeutic strategy that can target increased protein levels of ADAM17 and its sheddase activity that contribute to intestinal and systemic inflammation in treated HIV. The large repertoire of inflammatory mediators involved in ADAM17 sheddase activity places it as a pivotal orchestrator of several inflammatory pathways associated with morbidity in chronic treated HIV that make it an attractive therapeutic target.

CRISPR/dCas9 Transcriptional Activation of Endogenous Apolipoprotein AI and Paraoxonase 1 in Enterocytes Alleviates Endothelial Cell Dysfunction

Atherosclerosis is the main cause of cardiovascular diseases with high prevalence worldwide. A promising therapeutic strategy to reverse atherosclerotic process is to improve the athero-protective potential of high-density lipoproteins (HDL). Since the small intestine is a source of HDL, we aimed to activate transcription of the endogenous HDL major proteins, apolipoprotein AI (ApoAI) and paraoxonase 1 (PON1), in enterocytes, and to evaluate their potential to correct the pro-inflammatory status of endothelial cells (EC). Caco-2 enterocytes were transfected with CRISPR activation plasmids targeting ApoAI or PON1, and their gene and protein expression were measured in cells and conditioned medium (CM). ATP binding cassette A1 and G8 transporters (ABCA1, ABCG8), scavenger receptor BI (SR-BI), and transcription regulators peroxisome proliferator-activated receptor γ (PPARγ), liver X receptors (LXRs), and sirtuin-1 (SIRT1) were assessed. Anti-inflammatory effects of CM from transfected enterocytes were estimated through its ability to inhibit tumor necrosis factor α (TNFα) activation of EC. Transcriptional activation of ApoAI or PON1 in enterocytes induces: (i) increase of their gene and protein expression, and secretion in CM; (ii) stimulation of ABCA1/G8 and SR-BI; (iii) upregulation of PPARγ, LXRs, and SIRT1. CM from transfected enterocytes attenuated the TNFα-induced inflammatory and oxidative stress in EC, by decreasing TNF receptor 1, monocyte chemoattractant protein-1, and p22phox. In conclusion, transcriptional activation of endogenous ApoAI or PON1 in enterocytes by CRISPR/dCas9 system is a realistic approach to stimulate biogenesis and function of major HDL proteins which can regulate cholesterol efflux transporters and reduce the inflammatory stress in activated EC.

Association of anti-oxidative capacity of HDL with subclinical atherosclerosis in subjects with and without non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) patients are at a substantial risk for developing cardiovascular disease (CVD). High-density lipoprotein (HDL) is well known to have protective effects against the development of atherosclerotic CVD. One of the major antiatherogenic effects of HDL is its anti-oxidative function.

OBJECTIVES

This study investigated the association of anti-oxidative capacity of HDL with subclinical atherosclerosis in NAFLD and non-NAFLD subjects.

METHODS

A total of 143 subjects including 51 NAFLD and 92 control subjects were included in this case-control study. HDL oxidative index (HOI) was determined spectrophotometrically using a cell-free method in the presence of a fluorescent substrate dichlorofluorescein diacetate (DCFDA). Paraoxonase 1 (PON1) activity, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) plasma levels were assessed in both groups.

RESULTS

The NAFLD patients with impaired HDL anti-oxidative function (HOI  ≥ 1) had higher MDA levels, aspartate amino transferase (AST), liver stiffness (LS), and carotid intima-media thickness (cIMT) values compared to the controls. HDL oxidative index (HOI) was positively correlated with MDA levels and cIMT and negatively correlated with SOD activity.

CONCLUSIONS

Higher circulating levels of MDA were associated with the impaired anti-oxidative function of HDL in NAFLD. The impaired anti-oxidative capacity of HDL might be related to NAFLD severity and subclinical atherosclerosis in NAFLD patients.

MiR-223-3p levels in the plasma and atherosclerotic plaques are increased in aged patients with carotid artery stenosis; association with HDL-related proteins

BACKGROUND

Cardiovascular diseases are still the main cause of death worldwide. Our aim was to analyse the link between miR-223-3p levels, dysfunctional HDL and the age of patients with carotid artery stenosis (CAS).

METHODS AND RESULTS

Thirty-two CAS patients enrolled for endarterectomy were divided in 2 groups: aged over 65 years (n = 19) and under 65 years (n = 13). Plasma samples and atherosclerotic plaques from the carotid artery were collected from all patients. Plaque levels of miR-223-3p and its primary transcript (pri-miR-223) were assessed, together with Drosha, Dicer, apolipoprotein (apo)A-I, apoE and myeloperoxidase (MPO) gene expression. In the plasma and plaques, miR-223-3p expression levels were significantly increased in CAS patients over 65 years. Positive correlations between plaque miR-223-3p and pri-miR-223 levels with Drosha, apoA-I and MPO expression were observed. Significantly increased miR-223-3p levels in the plasma of CAS patients over 65 years were measured. Significant correlations between plasma miR-223-3p levels and HDL-related proteins were determined. The variance of plasma miR-223-3p levels was predicted significantly by the multiple regression models using either age, clinical variables, blood lipids or oxidative and inflammatory parameters. Receiver operator characteristic analysis revealed that plasma miR-223-3p levels and HDL-related proteins (MPO activity/apoA-I ratio, MPO specific activity) were correlated with advanced age.

CONCLUSIONS

Taken together, these data suggest that plasma levels of miR-223-3p are independently associated with ageing in CAS patients and that, correlated with parameters associated with dysfunctional HDL, could predict the aggravation of CAS in elderly patients.

High-Density Lipoprotein Subfractions: Much Ado about Nothing or Clinically Important?

High-density lipoproteins (HDL) are a heterogenous group of plasma molecules with a large variety in composition. There is a wide specter in lipid content and the number of different proteins that has been associated with HDL is approaching 100. Given this heterogeneity and the fact that the total amount of HDL is inversely related to the risk of coronary heart disease (CHD), there has been increasing interest in the function of specific HDL subgroups and in what way measuring and quantifying these subgroups could be of clinical importance in determining individual CHD risk. If certain subgroups appear to be more protective than others, it may also in the future be possible to pharmacologically increase beneficial and decrease harmful subgroups in order to reduce CHD risk. In this review we give a short historical perspective, summarize some of the recent clinical findings regarding HDL subclassifications and discuss why such classification may or may not be of clinical relevance.

Scavenger Receptor BI Induced by HDL From Coronary Heart Disease May Be Related to Atherosclerosis

This study aims to determine whether dysfunctional High Density Lipoprotein (HDL) influenced the expression of scavenger receptor class B type Ⅰ (SR-B1) to determine reverse cholesterol transport. Blood samples obtained from coronary heart disease patients confirmed by angiography were collected. HDL was extracted from the blood via ultracentrifugation. Then, the HDL was injected into apoE-/- mice, and the HepG2 cells cultured with Dulbecco's modified eagle medium (DMEM) were added the HDL extracted from coronary heart disease patients. As controls, normal cases without coronary heart disease (CHD) and patients with angina pectoris and acute myocardial infarction were used. The protein expression levels of SR-B1 were detected by western blot, and the lipid accumulation levels were detected by Oil Red O staining in both tissues and cell levels. These results revealed that the HDL obtained from CHD patients downregulate the SR-B1 expression in ex vitro and in vitro studies. In addition, dysfunctional HDL may result in lower SR-B1 expression levels. The degree of SR-B1 expression levels could be relative to the degree of coronary congestion. Along with the increase in severe coronary congestion, such as myocardial infarction, the SR-B1 expression levels were lower. The dysfunctional HDL derived from coronary heart disease patients decreased the expression of SR-B1, and promoted lipid accumulation.

Structure and Dynamics of Oxidized Lipoproteins In Vivo: Roles of High-Density Lipoprotein

Oxidative modification of lipoproteins is implicated in the occurrence and development of atherosclerotic lesions. Earlier studies have elucidated on the mechanisms of foam cell formation and lipid accumulation in these lesions, which is mediated by scavenger receptor-mediated endocytosis of oxidized low-density lipoprotein (oxLDL). Mounting clinical evidence has supported the involvement of oxLDL in cardiovascular diseases. High-density lipoprotein (HDL) is known as anti-atherogenic; however, recent studies have shown circulating oxidized HDL (oxHDL) is related to cardiovascular diseases. A modified structure of oxLDL, which was increased in the plasma of patients with acute myocardial infarction, was characterized. It had two unique features: (1) a fraction of oxLDL accompanied oxHDL, and (2) apoA1 was heavily modified, while modification of apoB, and the accumulation of oxidized phosphatidylcholine (oxPC) and lysophosphatidylcholine (lysoPC) was less pronounced. When LDL and HDL were present at the same time, oxidized lipoproteins actively interacted with each other, and oxPC and lysoPC were transferred to another lipoprotein particle and enzymatically metabolized rapidly. This brief review provides a novel view on the dynamics of oxLDL and oxHDL in circulation.

Subpopulations of High-Density Lipoprotein: Friends or Foes in Cardiovascular Disease Risk in Chronic Kidney Disease?

Dyslipidemia is a major traditional risk factor for cardiovascular disease (CVD) in chronic kidney disease (CKD) patients, although the altered lipid profile does not explain the number and severity of CVD events. High-density lipoprotein (HDL) is a heterogeneous (size, composition, and functionality) population of particles with different atherogenic or atheroprotective properties. HDL-cholesterol concentrations per se may not entirely reflect a beneficial or a risk profile for CVD. Large HDL in CKD patients may have a unique proteome and lipid composition, impairing their cholesterol efflux capacity. This lack of HDL functionality may contribute to the paradoxical coexistence of increased large HDL and enhanced risk for CVD events. Moreover, CKD is associated with inflammation, oxidative stress, diabetes, and/or hypertension that are able to interfere with the anti-inflammatory, antioxidative, and antithrombotic properties of HDL subpopulations. How these changes interfere with HDL functions in CKD is still poorly understood. Further studies are warranted to fully clarify if different HDL subpopulations present different functionalities and/or atheroprotective effects. To achieve this goal, the standardization of techniques would be valuable.

Understanding Accelerated Atherosclerosis in Systemic Lupus Erythematosus: Toward Better Treatment and Prevention

Systemic lupus erythematosus (SLE) carries a significant risk of cardiovascular disease (CVD). The prevalence of premature CVD is especially noteworthy because it occurs in premenopausal women with SLE who would otherwise have very low rates of CVD. While traditional risk factors likely play a role in development of CVD in the setting of SLE, they do not fully explain the excess risk. The pathogenesis of CVD in SLE is not fully understood, but the inflammatory nature of SLE is believed to be a key factor in accelerating atherosclerosis. Systemic inflammation may lead to an abnormal lipid profile with elevated triglycerides, total cholesterol, and low-density lipoprotein cholesterol and dysfunctional high-density lipoprotein cholesterol. Additionally, the inflammatory milieu of SLE plasma promotes endothelial dysfunction and vascular injury, early steps in the progression of atherosclerotic CVD. Despite the overall headway that has been achieved in treating lupus, innovative therapeutics specifically targeting the progression of atherosclerosis within the lupus population are currently lacking. However, there have been advancements in the development of promising modalities for diagnosis of subclinical atherosclerosis and detection of high CVD risk patients. Due to the significant impact of CVD on morbidity and mortality, research addressing prevention and treatment of CVD in SLE needs to be prioritized. This review explores the intricate interplay of SLE-specific properties that contribute to atherosclerosis and CVD within this population, as well as screening methods and possible therapies.

Alginate/poloxamer hydrogel obtained by thiol-acrylate photopolymerization for the alleviation of the inflammatory response of human keratinocytes

Hydrogel-based wound dressings have been intensively studied as promising materials for wound healing and care. The mixed-mode thiol-acrylate photopolymerization is used in this paper for alginate/poloxamer hydrogels formation. First, the alginate was modified with thiol groups using the esterification reaction with cysteamine, and second, the terminal hydroxyl groups of poloxamer were esterified with acryloyl chloride to introduce polymerizable acrylate groups. Finally, the cross-linking reaction between the two macromers was performed to produce degradable alginate/poloxamer hydrogels. The optimum conditions for the photo-initiated reaction were studied in order to obtain high gel fractions. The resulting hydrogels have high swelling capacity in simulated physiological conditions, good elasticity and strength, and appropriate porosity, some of the physico-chemical properties required for their applications as wound dressings/patches. The biological assays show that the alginate/poloxamer hydrogels induce proliferation of human keratinocyte and have an anti-inflammatory effect on lipopolysaccharides (LPS)-activated keratinocytes by inhibiting the extracellular signal-regulated kinases (ERK)/ nuclear factor (NF)-kB/ tumor necrosis factor (TNF)-α signalling pathway. Taken together, the results showed that the chemical cross-linked alginate/poloxamer hydrogels may function as a dressing/patch applied directly on the skin lesion to heal the wound by reducing the exacerbated inflammation, the main cause of wound healing delay and local infection.

The role of high-density lipoprotein cholesterol, apolipoprotein A and paraoxonase-1 in the pathophysiology of neuroprogressive disorders

Lowered high-density lipoprotein (HDL) cholesterol has been reported in major depressive disorder, bipolar disorder, first episode of psychosis, and schizophrenia. HDL, its major apolipoprotein component, ApoA1, and the antioxidant enzyme paraoxonase (PON)1 (which is normally bound to ApoA1) all have anti-atherogenic, antioxidant, anti-inflammatory, and immunomodulatory roles, which are discussed in this paper. The paper details the pathways mediating the anti-inflammatory effects of HDL, ApoA1 and PON1 and describes the mechanisms leading to compromised HDL and PON1 levels and function in an environment of chronic inflammation. The molecular mechanisms by which changes in HDL, ApoA1 and PON1 might contribute to the pathophysiology of the neuroprogressive disorders are explained. Moreover, the anti-inflammatory actions of ApoM-mediated sphingosine 1-phosphate (S1P) signalling are reviewed as well as the deleterious effects of chronic inflammation and oxidative stress on ApoM/S1P signalling. Finally, therapeutic interventions specifically aimed at improving the levels and function of HDL and PON1 while reducing levels of inflammation and oxidative stress are considered. These include the so-called Mediterranean diet, extra virgin olive oil, polyphenols, flavonoids, isoflavones, pomegranate juice, melatonin and the Mediterranean diet combined with the ketogenic diet.

[The Current Significance of Measuring HDL-Cholesterol in Cardiovascular Risk Assessment]

The Current Significance of Measuring HDL-Cholesterol in Cardiovascular Risk Assessment Abstract. In clinical practice, high-density lipoprotein cholesterol (HDL-C) levels are frequently used for cardiovascular risk prediction. HDL particles perform numerous functions that theoretically protect against atherosclerosis. Accordingly, extensive studies have clearly demonstrated that low HDL-C is an important independent risk factor for cardiovascular diseases. However, it is now considered questionable whether very high HDL-C levels are always cardioprotective. This may be explained by the structural heterogeneity of HDL particles and the loss of HDL protective functions in the context of disease, which cannot be detected by the simple measurement of HDL-C. In the future new markers of the functional capacity of HDL particles may replace HDL-C as a traditional parameter for cardiovascular risk assessment.

Endothelial Dysfunction in Diabetes Is Aggravated by Glycated Lipoproteins; Novel Molecular Therapies

Diabetes and its vascular complications affect an increasing number of people. This disease of epidemic proportion nowadays involves abnormalities of large and small blood vessels, all commencing with alterations of the endothelial cell (EC) functions. Cardiovascular diseases are a major cause of death and disability among diabetic patients. In diabetes, EC dysfunction (ECD) is induced by the pathological increase of glucose and by the appearance of advanced glycation end products (AGE) attached to the plasma proteins, including lipoproteins. AGE proteins interact with their specific receptors on EC plasma membrane promoting activation of signaling pathways, resulting in decreased nitric oxide bioavailability, increased intracellular oxidative and inflammatory stress, causing dysfunction and finally apoptosis of EC. Irreversibly glycated lipoproteins (AGE-Lp) were proven to have an important role in accelerating atherosclerosis in diabetes. The aim of the present review is to present up-to-date information connecting hyperglycemia, ECD and two classes of glycated Lp, glycated low-density lipoproteins and glycated high-density lipoproteins, which contribute to the aggravation of diabetes complications. We will highlight the role of dyslipidemia, oxidative and inflammatory stress and epigenetic risk factors, along with the specific mechanisms connecting them, as well as the new promising therapies to alleviate ECD in diabetes.

Regulation of microRNAs in high-fat diet induced hyperlipidemic hamsters

Dyslipidemia is a documented risk factor for cardiovascular diseases and other metabolic disorders. Therefore, the analysis of hyperlipidemia (HL)-related miRNAs is a potential approach for achieving new prognostic markers in lipid-metabolism related diseases. We aimed to analyze specific distribution of miRNAs in different tissues from HL animals. Golden Syrian hamsters were fed either regular chow (NL) or high-fat diet (HL) for 12 weeks. Microarray miRNAs profiling was performed in liver, heart and small intestine and data analyzed by R-studio software. Functional enrichment bioinformatics analysis was performed using miRWalk and DAVID tools. We observed a dysregulation of miRNAs in HL tissues evidencing a discrete distribution in the heart-liver axis and three lipid metabolism-related miRNAs were identified: hsa-miR-223-3p, hsa-miR-21-5p, and hsa-miR-146a-5p. Expression levels of these miRNAs were increased in HL livers and hearts. Functional bioinformatics analysis showed involvement of these miRNAs in the regulation of biological processes altered in HL conditions such as lipid metabolic process, fat cell differentiation, regulation of smooth muscle cells and cardiac septum development. We identified a set of miRNAs dysregulated in different tissues of HFD-induced HL hamsters. These findings motivate further studies aiming to investigate novel molecular mechanisms of lipid metabolism and atherogenic HL.

Three two-site apoA-I immunoassays using phage expressed detector antibodies - Preliminary clinical evaluation with cardiac patients

High density lipoproteins (HDL) are a heterogenous group of subpopulations differing in protein/lipid composition and in their anti-atherogenic function. There is a lack of specific and robust assays which can target the functionality of HDL with respect to atherosclerosis. With recently generated CAD HDL targeted, single chain recombinant antibodies (scFvs) we set out to design and optimize apo A-I tests to compare it with conventional HDL-C and apo A-I analyses for diagnosis and risk assessment of coronary artery disease (CAD) and its outcome. Three highly sensitive two-site apo A-I assays: 022-454, 109-121 and 110-525 were optimized. A preliminary clinical evaluation of these assays, after proper sample dilution procedure, was performed using samples derived from 195 chest pain patients (myocardial infarction (MI), n = 86 and non-MI, n = 109), collected at the time of admission and at discharge from hospital (hospital stay ≤ 24 h). The clinical performance of the assays was compared with apo A-I measured with polyclonal anti-apo A-I antibody using conventional ELISA. Apo A-I data was in addition compared with HDL-C concentration of the samples. The concentration of apo A-I was significantly lower in MI patients than in non-MI individuals with assay 022-454 (admission and discharge samples, P < 0.0001 and = 0.004); assay 109-121 (admission and discharge samples, P = 0.04 and 0.0009), and, ELISA based apo A-I test (admission and discharge samples, P = 0.008 and < 0.0001). HDL-C (admission and discharge samples, P = 0.002 and P = 0.01) was also significantly lower in MI patients. In Kaplan- Meier analysis, two-site assay 109-121 assay predicted mortality from admission samples at 1.5 yrs (whole cohort, P = 0.01 and in MI patients, P = 0.05) and at 6 months (whole cohort, P = 0.04). Assay 110-525 predicted mortality at 1.5 yrs from admission samples of non-MI patients (P = 0.01) and at 6 months from whole discharge sample cohort (P = 0.04). Polyclonal anti-apo A-I based conventional assay predicted mortality at 1.5 yrs from admission samples of whole cohort (P = 0.03). Two-site apo A-I assay 022-454 and HDL-C provided no capability of predicting mortality in the whole cohort or any sub-group. In conclusion, two of the tested recombinant apo A-I antibody combinations (sc 109-121 and sc 110-525) display promising outcome to improve diagnosis and prediction of future cardiac events in cardiac patients over polyclonal apo A-I ELISA and HDL-C assays. The noted differences, while interesting, are preliminary and need however to be verified in extensive cohorts of pathological cardiac conditions and healthy controls.

A new sponge-type hydrogel based on hyaluronic acid and poly(methylvinylether-alt-maleic acid) as a 3D platform for tumor cell growth

A new sponge-type hydrogel was obtained by cross-linking hyaluronic acid (HA) and poly(methylvinylether-alt-maleic acid) P(MVE-alt-MA) through a solvent-free thermal method. The sponge-type hydrogel was characterized and checked as a support for cell growth. The influence of concentration and weight ratio of polymers on the morphology and hydrogel stability was investigated. The total polymers concentration of 3% (w/w) and the weight ratio of 1:1 were optimal for the synthesis of a stable hydrogel (HA³P50) and to promote cell proliferation. The swelling measurements revealed a high-water absorption capacity of the hydrogel in basic medium. Diphenhydramine (DPH), lidocaine (Lid) and propranolol (Prop) were loaded within the hydrogel as a model drugs to investigate the ability of drug transport and release. In vitro studies revealed that HA³P50 hydrogel promoted the adhesion and proliferation of human hepatocellular carcinoma cell line HepG2, providing a good support for 3D cell culture to obtain surrogate tumor scaffold suitable for preclinical anti-cancer drug screening.

Spp24 is associated with endocytic signalling, lipid metabolism, and discrimination of tissue integrity for 'leaky-gut' in inflammatory bowel disease

Epithelial barrier injury allows contaminants to cross-over into the blood stream and trigger an inflammatory response, contributing to inflammatory bowel disease (IBD). Currently there is no single test that can reliably diagnose intestinal mucosal barrier function or measure impaired epithelial cell integrity associated with increasing permeability. Here, we assess the association between serum proteins and small intestinal permeability as detected by confocal laser endomicroscopy (CLE); in particular the known IBD marker—secreted phosphoprotein 24 (SPP24) and its binding partners; and use developed monoclonal antibodies to assess the role of SPP24 in mucosal healing. Sera were obtained from 28 IBD patients and non-IBD controls undergoing CLE with scores ranging from low to high permeability, as well as active ulcerative colitis from 53 patients undergoing fecal microbiota transplant therapy (FMT). Higher permeability associated with altered lipid metabolism, heightened innate immune response and junctional protein signalling in UC patients. A correlation between increasing leak and SPP24 peptide was observed. There is a strong indication of the novel role of SPP24 in gut barrier dysfunction particularly in ulcerative colitis. Its correlation to the established CLE for monitoring permeability has the potential to provide a blood based parallel to monitor and guide therapy more readily across a broad spectrum of illnesses for which ‘leak’ dominates the pathology.

Phenolic Compounds Exerting Lipid-Regulatory, Anti-Inflammatory and Epigenetic Effects as Complementary Treatments in Cardiovascular Diseases

Atherosclerosis is the main process behind cardiovascular diseases (CVD), maladies which continue to be responsible for up to 70% of death worldwide. Despite the ongoing development of new and potent drugs, their incomplete efficacy, partial intolerance and numerous side effects make the search for new alternatives worthwhile. The focus of the scientific world turned to the potential of natural active compounds to prevent and treat CVD. Essential for effective prevention or treatment based on phytochemicals is to know their mechanisms of action according to their bioavailability and dosage. The present review is focused on the latest data about phenolic compounds and aims to collect and correlate the reliable existing knowledge concerning their molecular mechanisms of action to counteract important risk factors that contribute to the initiation and development of atherosclerosis: dyslipidemia, and oxidative and inflammatory-stress. The selection of phenolic compounds was made to prove their multiple benefic effects and endorse them as CVD remedies, complementary to allopathic drugs. The review also highlights some aspects that still need clear scientific explanations and draws up some new molecular approaches to validate phenolic compounds for CVD complementary therapy in the near future.

Lipid-Lowering Agents

Several new or emerging drugs for dyslipidemia owe their existence, in part, to human genetic evidence, such as observations in families with rare genetic disorders or in Mendelian randomization studies. Much effort has been directed to agents that reduce LDL (low-density lipoprotein) cholesterol, triglyceride, and Lp[a] (lipoprotein[a]), with some sustained programs on agents to raise HDL (high-density lipoprotein) cholesterol. Lomitapide, mipomersen, AAV8.TBG.hLDLR, inclisiran, bempedoic acid, and gemcabene primarily target LDL cholesterol. Alipogene tiparvovec, pradigastat, and volanesorsen primarily target elevated triglycerides, whereas evinacumab and IONIS-ANGPTL3-L_Rx target both LDL cholesterol and triglyceride. IONIS-APO(a)-L_Rx targets Lp(a).

Hyperlipidemia Determines Dysfunctional HDL Production and Impedes Cholesterol Efflux in the Small Intestine: Alleviation by Ginger Extract

SCOPE

To assess the impact of ginger extract (GIN) in stimulating the production of quality HDL and the cholesterol efflux in the small intestine (SI), key processes in the management of hyperlipidemia (HL)-induced hepatic steatosis, and atherosclerosis.

METHODS AND RESULTS

Three groups of hamsters are used: (i) N, fed standard diet, (ii) HL, fed high-fat diet for 21 weeks, and (iii) HL-GIN, HL treated with GIN for the last 5 weeks of diet. Apolipoprotein A-I (apoA-I), malondialdehyde-apoA-I (MDA-apoA-I), paraoxonase1 (PON1), and myeloperoxidase (MPO) are measured in plasma and SI. ATP-binding cassette A1 transporter (ABCA1), ABCG5/G8, liver X receptor α/β (LXRα/β), peroxisome proliferator-activated receptor γ (PPARγ), and sirtuin1 (SIRT1) are assessed in the SI. Results show that in HL plasma, GIN decreases MDA-apoA-I, MPO/PON1 ratio and increases HDL-cholesterol/total cholesterol. In HL-SI, GIN decreases MDA-apoA-I and MPO, increases ApoA-I, PON1, and ABCA1, and restores cholesterol efflux disturbed by HL (SIRT1-LXRα/β-PPARγ-ABCG8). GIN administration is associated with the reduction of the aortic valves lipid-deposits.

CONCLUSION

In HL conditions, GIN stimulates the functional HDL production by restoring apoA-I quality and quantity through inhibition of the oxidative stress, and increases cholesterol efflux in the SI. These effects are associated with the restoration of SIRT1-LXRα/β-PPARγ pathway.

Modification of HDL by reactive aldehydes alters select cardioprotective functions of HDL in macrophages

While increased levels of high-density lipoprotein (HDL)-cholesterol correlate with protection against cardiovascular disease, recent findings demonstrate that HDL function, rather than HDL-cholesterol levels, may be a better indicator of cardiovascular risk. One mechanism by which HDL function can be compromised is through modification by reactive aldehydes such as acrolein (Acro), 4-hydroxynonenal, and malondialdehyde (MDA). In this study, we tested the hypothesis that modification of HDL with reactive aldehydes would impair HDL's athero-protective functions in macrophages. Compared to native HDL, Acro- and MDA-modified HDL have impaired abilities to promote migration of primary peritoneal macrophages isolated from C57BL6/J mice. Incubation of macrophages with MDA-HDL also led to an increased ability to generate reactive oxygen species. Our studies revealed that the changes in HDL function following aldehyde modification are likely not through activation of canonical nuclear factor-kappa B signaling pathways. Consistent with this finding, treatment of either noncholesterol-loaded macrophages or foam cells with modified forms of HDL does not lead to significant changes in expression levels of inflammatory markers. Importantly, our data also demonstrate that changes in HDL function are dependent on the type of modification present on the HDL particle. Our findings suggest that modification of HDL with reactive aldehydes can impair some, but not all, of HDL's athero-protective functions in macrophages.

Ten years in: APOL1 reaches beyond the kidney

PURPOSE OF REVIEW

APOL1 nephropathy risk variants drive most of the excess risk of chronic kidney disease (CKD) seen in African Americans, but whether the same risk variants account for excess cardiovascular risk remains unclear. This mini-review highlights the controversies in the APOL1 cardiovascular field.

RECENT FINDINGS

In the past 10 years, our understanding of how APOL1 risk variants contribute to renal cytotoxicity has increased. Some of the proposed mechanisms for kidney disease are biologically plausible for cells and tissues relevant to cardiovascular disease (CVD), but cardiovascular studies published since 2014 have reported conflicting results regarding APOL1 risk variant association with cardiovascular outcomes. In the past year, several studies have also contributed conflicting results from different types of study populations.

SUMMARY

Heterogeneity in study population and study design has led to differing reports on the role of APOL1 nephropathy risk variants in CVD. Without consistently validated associations between these risk variants and CVD, mechanistic studies for APOL1's role in cardiovascular biology lag behind.

The Protective Role of Adiponectin for Lipoproteins in End-Stage Renal Disease Patients: Relationship with Diabetes and Body Mass Index

Cardiovascular disease (CVD) events are the main causes of death in end-stage renal disease (ESRD) patients on dialysis. The number and severity of CVD events remain inappropriate and difficult to explain by considering only the classic CVD risk factors. Our aim was to clarify the changes and the relationship of lipoprotein subfractions with other CVD risk factors, namely, body mass index (BMI) and adipokines, inflammation and low-density lipoprotein (LDL) oxidation, and the burden of the most prevalent comorbidities, diabetes mellitus (DM) and hypertension (HT). We studied 194 ESRD patients on dialysis and 22 controls; lipid profile, including lipoprotein subpopulations and oxidized LDL (oxLDL), C-reactive protein (CRP), adiponectin, leptin, and paraoxonase 1 activity were evaluated. Compared to controls, patients presented significantly lower levels of cholesterol, high-density lipoprotein cholesterol (HDLc), LDLc, oxLDL, and intermediate and small HDL and higher triglycerides, CRP, adiponectin, large HDL, very-low-density lipoprotein (VLDL), and intermediate-density lipoprotein- (IDL) B. Adiponectin levels correlated positively with large HDL and negatively with intermediate and small HDL, oxLDL/LDLc, and BMI; patients with DM (n = 17) and with DM+HT (n = 70), as compared to patients without DM or HT (n = 69) or only with HT (n = 38), presented significantly higher oxLDL, oxLDL/LDLc, and leptin and lower adiponectin. Obese patients (n = 45), as compared to normoponderal patients (n = 81), showed lower HDLc, adiponectin, and large HDL and significantly higher leptin, VLDL, and intermediate and small HDL. In ESRD, the higher adiponectin seems to favor atheroprotective HDL modifications and protect LDL particles from oxidative atherogenic changes. However, in diabetic and obese patients, adiponectin presents the lowest values, oxLDL/LDLc present the highest ones, and the HDL profile is the more atherogenic. Our data suggest that the coexistence of DM and adiposity in ESRD patients on dialysis contributes to a higher CVD risk, as showed by their lipid and adipokine profiles.

Current Therapies Focused on High-Density Lipoproteins Associated with Cardiovascular Disease

High-density lipoproteins (HDL) comprise a heterogeneous family of lipoprotein particles divided into subclasses that are determined by density, size and surface charge as well as protein composition. Epidemiological studies have suggested an inverse correlation between High-density lipoprotein-cholesterol (HDL-C) levels and the risk of cardiovascular diseases and atherosclerosis. HDLs promote reverse cholesterol transport (RCT) and have several atheroprotective functions such as anti-inflammation, anti-thrombosis, and anti-oxidation. HDLs are considered to be atheroprotective because they are associated in serum with paraoxonases (PONs) which protect HDL from oxidation. Polyphenol consumption reduces the risk of chronic diseases in humans. Polyphenols increase the binding of HDL to PON1, increasing the catalytic activity of PON1. This review summarizes the evidence currently available regarding pharmacological and alternative treatments aimed at improving the functionality of HDL-C. Information on the effectiveness of the treatments has contributed to the understanding of the molecular mechanisms that regulate plasma levels of HDL-C, thereby promoting the development of more effective treatment of cardiovascular diseases. For that purpose, Scopus and Medline databases were searched to identify the publications investigating the impact of current therapies focused on high-density lipoproteins.

Weight loss achieved by bariatric surgery modifies high-density lipoprotein subfractions and low-density lipoprotein oxidation towards atheroprotection

OBJECTIVES

Weight loss achieved by laparoscopic adjustable gastric banding (LAGB) induces an increase in high-density lipoprotein cholesterol (HDLc) but a small effect on low-density lipoprotein (LDL), although changes in their quality (size and composition) are uncertain. Our aim was to study the impact of weight loss, achieved 13-months after LAGB, on inflammation and dyslipidemia, focusing on HDL and LDL subfractions, and oxidized LDL (oxLDL).

DESIGN & METHODS

We evaluated standard lipid profile, HDL and LDL subfractions, oxLDL, interleukin (IL)-6 and C-reactive protein (CRP), in twenty obese patients, before (T0) and 13-months after LAGB (T1), and in seventeen healthy controls.

RESULTS

At T1, patients showed lower body weight (12% median weight loss) and anthropometric indices; reduction in TG, atherogenic indices, oxLDL, oxLDL/LDL ratio, CRP and IL-6, and enhancement in HDLc; an increase in large HDL and intermediate HDL subfractions, and a decrease in small HDL subfraction; LDL subfractions were not modified. Percentual change (%Δ) of oxLDL, from T0 to T1, correlated significantly and positively with %Δ of small HDL subfraction and with %Δ of body mass index.

CONCLUSIONS

Weight loss induced atheroprotective changes on inflammation, and lipid profile, enhancing larger HDL, the more atheroprotective subfraction, reducing the less protective subclass, small HDL, and reducing oxLDL and oxLDL/LDL ratio. Quality of lipoproteins appears useful cardiovascular risk biomarkers, deserving further studies.

Zingiber officinale extract administration diminishes steroyl-CoA desaturase gene expression and activity in hyperlipidemic hamster liver by reducing the oxidative and endoplasmic reticulum stress

BACKGROUND

Stearoyl CoA desaturases (SCD) are enzymes that convert saturated to monounsaturated fatty acids and have increased activity in hepatic steatosis.

PURPOSE

We aimed to investigate the potential of ginger extract (GIN) to modulate the liver SCD1 expression and activity in hyperlipidemic (HL) conditions, in order to lower lipid accumulation in the steatotic liver.

STUDY DESIGN/METHODS

Male Golden Syrian hamsters were divided in three groups: (i) fed with standard chow (N), (ii) fed with standard chow plus 3% cholesterol and 15% butter for 21 weeks (HL), (iii) HL treated with GIN (800 µg/kg body weight/day) in the last 5 weeks of fat diet (HL-GIN). Cholesterol (C), triglycerides (TG), non-esterified fatty acids (NEFA), SCD1 estimated activity (C16:1n7/C16:0; C18:1n9/C18:0) and gene expression, acetyl-CoA carboxylase (ACC), thiobarbituric acid reactive substances (TBARS), paraoxonase1 (PON1) and myeloperoxidase (MPO) were determined in the plasma and liver of all hamsters. We measured protein expression of endoplasmic reticulum stress (ERS) markers, gene and protein expression of liver X receptor α/β (LXRα/β), peroxisome proliferator-activated receptor γ (PPARγ), ATP-binding cassette sub-family G member 5/8 (ABCG5/G8) and 7α-hydroxylase1 (CYP7A1) in all hamsters' livers.

RESULTS

In plasma, in HL-GIN versus HL hamsters, SCD1 estimated activity was lower (27%; 15%, p < 0.05), NEFA levels decreased by 91%, p < 0.001, while C and TG levels did not vary; the oxidative stress expressed as MPO and TBARS levels decreased (15%; 11%, p < 0.01), while PON1 protein increased (75%, p < 0.05). In the liver of HL-GIN versus HL, C, TG, NEFA, MPO and TBARS levels decreased (8-40%, p < 0.05) and PON1 protein levels increased (30%, p < 0.05), SCD1 estimated activity decreased (8%; 9%, p < 0.05), in parallel with the reduced gene expression of SCD1 and ACC (70-80%, p < 0.05). The protein expression of the ERS sensors decreased (30-65%, p < 0.05), while that of ABCG5/G8, CYP7A1, LXRα/β and PPARγ increased in HL-GIN (20-30%, p < 0.05) versus HL liver.

CONCLUSION

GIN reduces SCD1 estimated activity and expression, as well as the lipids accumulated in the livers of HL hamsters. This is achieved through a mechanism involving the decrease of the oxidative and ERS, and the enhancement of cholesterol efflux.

Activity of paraoxonase 1 (PON1) on HDL2 and HDL3 subclasses in renal disease

INTRODUCTION

Cardiovascular complications, as the main cause of mortality in renal patients, are followed with altered lipoproteins composition. Considering that paraoxonase-1 (PON1) is an anti-oxidative enzyme located mainly on HDL particles, the current study has aim to investigate whether failure of kidney function leads to changes in the distribution of PON1 activity between different HDL subclasses.

MATERIALS AND METHODS

In 77 renal patients (21 chronic kidney disease (CKD) and 56 end stage renal disease (ESRD) patients on dialysis) and 20 healthy subjects PON1 activity on HDL₂ and HDL₃ subclasses was determined by zymogram method that combines gradient gel electrophoresis separation of HDL subclasses and measurement of PON1 activity in the same gel.

RESULTS

Serum paraoxonase (p<0.01) and arylesterase activity (p<0.001) of PON1 as well as its concentration (p<0.01) were significantly lower in CKD and ESRD patients compared to controls. Relative proportion of HDL₃ subclasses was higher in ESRD patients than in healthy participants, while HDL₂ subclasses was significantly decreased in CKD (p<0.05) and ESRD (p<0.001) patients, as compared to controls. Furthermore, control subjects had higher PON1 activity on HDL₂ (CKD and ESRD patients p<0.001) and HDL₃ (CKD p<0.05; ESRD patients p<0.001) subclasses in comparison with the both patients groups. Also, significant negative correlation was found between paraoxonase activity of PON1 in serum and creatinine concentration (ρ=-0.373, p<0.01).

CONCLUSIONS

This study showed that altered HDL subclasses distribution, changed PON1 activities on different HDL subclasses as well as diminished anti-oxidative protection could be important factors in atherosclerosis development in CKD and ESRD patients.

The impact of myeloperoxidase on HDL function in myocardial infarction

PURPOSE OF REVIEW

The focus in cardiovascular research is shifting from determining mass HDL cholesterol levels toward investigating HDL functionalities as biomarker for cardiovascular disease. Myeloperoxidase (MPO), a main effector enzyme of the innate immune system, is increasingly implicated to negatively impact HDL function by various chemical modifications of HDL-associated proteins. This review summarizes recent insights how MPO affects HDL function in the setting of acute myocardial infarction (MI), mainly focusing on human data.

RECENT FINDINGS

First the mechanisms how MPO renders HDL particles dysfunctional and the usefulness of MPO as prospective biomarker for MI incidence and outcomes are described. Then the evidence for MPO causing specific HDL function impairments in MI and the clinical value of these observations is discussed in the context of the different HDL function assays employed.

SUMMARY

MPO modification of HDL in acute MI generates dysfunctional HDL. Features of HDL dysfunction can be used to stratify MI patients and seem associated with outcomes. More prospective studies are warranted to explore, if MPO-modified HDL is causally linked to severity and outcomes of MI. If this could be established, MPO would represent an attractive target to improve HDL dysfunction in MI and provide clinical benefit for patients.

High-density lipoprotein (HDL) functionality and its relevance to atherosclerotic cardiovascular disease

Several prospective epidemiological studies have shown that there is a clear inverse relationship between serum high-density lipoprotein-cholesterol (HDL-C) concentrations and risk for coronary heart disease (CHD), even at low-density lipoprotein-cholesterol (LDL-C) levels below 70 mg/dL. However, more recent evidence from genetic studies and clinical research has come to challenge the long-standing notion that higher HDL-C levels are always beneficial, while lower HDL-C levels are always detrimental. Thus, it becomes apparent that HDL functionality plays a much more important role in atheroprotection than circulating HDL-C levels. HDL cholesterol efflux capacity (CEC) from macrophages is a key metric of HDL functionality and exhibits a strong inverse association with both carotid intima-media thickness and the likelihood of angiographic coronary artery disease (CAD), independent of the HDL-C level. Thus, extensive research is being conducted to identify new agents with a favorable side effect profile, which would be able to enhance CEC, improve HDL functionality and potentially decrease cardiovascular risk. This review aims to present and discuss the current clinical and scientific evidence pertaining to the significance of HDL functionality over the actual HDL-C concentration in mediating the favorable effects on the cardiovascular system. Thus, we conducted a PubMed search until December 2017 through the English literature using the search terms ‘HDL function/functionality’, ‘HDL properties’, ‘cardiovascular risk’ and ‘cholesterol efflux capacity’. We also included references from the articles identified and publications available in the authors’ libraries.

New medications targeting triglyceride-rich lipoproteins: Can inhibition of ANGPTL3 or apoC-III reduce the residual cardiovascular risk?

Remarkably good results have been achieved in the treatment of atherosclerotic cardiovascular diseases (CVD) by using statin, ezetimibe, antihypertensive, antithrombotic, and PCSK9 inhibitor therapies and their proper combinations. However, despite this success, the remaining CVD risk is still high. To target this residual risk and to treat patients who are statin-intolerant or have an exceptionally high CVD risk for instance due to familial hypercholesterolemia (FH), new therapies are intensively sought. One pathway of drug development is targeting the circulating triglyceride-rich lipoproteins (TRL) and their lipolytic remnants, which, according to the current view, confer a major CVD risk. Angiopoietin-like protein 3 (ANGPTL3) and apolipoprotein C-III (apoC-III) are at present the central molecular targets for therapies designed to reduce TRL, and there are new drugs emerging that suppress their expression or inhibit the function of these two key proteins. The medications targeting these components are biological, either human monoclonal antibodies or antisense oligonucleotides. In this article, we briefly review the mechanisms of action of ANGPTL3 and apoC-III, the reasons why they have been considered promising targets of novel therapies for CVD, as well as the current status and the most important results of their clinical trials.