The HDL hypothesis: does high-density lipoprotein protect from atherosclerosis?

Lipidomic analyses reveal potential biomarkers for predicting death and heart failure after acute myocardial infarction

Background Acute myocardial infarction (AMI) and postmyocardial infarction heart failure (pMIHF) have high mortality rates worldwide. This study aimed to explore lipidomic profiles and identify potential biomarkers for the prediction of death and heart failure (HF) after AMI. Methods All serum samples were collected at Xuanwu Hospital, Capital Medical University, and their clinical characteristics and lipidomic profiles were analyzed in different groups. LC-MS/MS was used for lipidomic analyses, and underlying biomarkers were screened by receiver operating characteristic (ROC) curve analysis. Results Lipidomic analyses of the survival and nonsurvival groups revealed that the decrease of the content of SM (d18:1/22:0), PE (P-20:1/18:0), PC (18:2), LPE (18:2), PE (P-20:0/18:0), LPC (18:0) and PC (20:0/20:3) while increase of the content of PG (18:1/18:1) could increase the risk of death after AMI. In parallel, the lipidomic analysis of the HF and non-HF groups revealed that the decrease of the content of PC (20:3/20:4), LPC (20:3), LPC (18:0), LPC (18:2), LPC (20:0), LPC (18:3), LPE (16:1) and PC (18:2/20:3) could increase the risk of HF after AMI. Conclusion Several lipids could be potential biomarkers for the prediction of death and HF after AMI.

High-density lipoprotein in diabetes: Structural and functional relevance

Low levels of high-density lipoprotein-cholesterol (HDL-C) is considered a major cardiovascular risk factor. However, recent studies have suggested a more U-shaped association between HDL-C and cardiovascular disease. It has been shown that the cardioprotective effect of HDL is related to the functions of HDL particles rather than their cholesterol content. HDL particles are highly heterogeneous and have multiple functions relevant to cardiometabolic conditions including cholesterol efflux capacity, anti-oxidative, anti-inflammatory, and vasoactive properties. There are quantitative and qualitative changes in HDL as well as functional abnormalities in both type 1 and type 2 diabetes. Non-enzymatic glycation, carbamylation, oxidative stress, and systemic inflammation can modify the HDL composition and therefore the functions, especially in situations of poor glycemic control. Studies of HDL proteomics and lipidomics have provided further insights into the structure-function relationship of HDL in diabetes. Interestingly, HDL also has a pleiotropic anti-diabetic effect, improving glycemic control through improvement in insulin sensitivity and β-cell function. Given the important role of HDL in cardiometabolic health, HDL-based therapeutics are being developed to enhance HDL functions rather than to increase HDL-C levels. Among these, recombinant HDL and small synthetic apolipoprotein A-I mimetic peptides may hold promise for preventing and treating diabetes and cardiovascular disease.

Association of Three Novel Inflammatory Markers: Lymphocyte to HDL-C Ratio, High-Sensitivity C-Reactive Protein to HDL-C Ratio and High-Sensitivity C-Reactive Protein to Lymphocyte Ratio With Metabolic Syndrome

OBJECTIVE

We aimed to compare the association of three novel inflammatory indicators with metabolic syndrome (MetS) among Mashhad stroke and heart atherosclerotic disorder (MASHAD) cohort participants.

METHODS

According to the International Diabetes Federation (IDF) criteria, the cohort participants were divided into the MetS(+) and MetS(-) groups. The lymphocyte to high-density lipoprotein cholesterol (HDL-C) ratio (LHR), high-sensitivity C-reactive protein (hs-CRP) to HDL-C ratio (HCHR) and hs-CRP to lymphocyte ratio (HCLR) were calculated and were compared between the groups. Binary logistic regression (LR) analysis was performed to find the association of the indices with the presence of MetS among men and women. Receiver-operating characteristic (ROC) curve analysis was used to establish cut-off values in predicting MetS for men and women. p-Values <0.05 were considered as statistically significant.

RESULTS

Among a total of 8890 participants (5500 MetS(-) and 3390 MetS(+)), LHR, HCHR and HCLR were significantly higher in the MetS(+) group than in MetS(-) group (p < 0.001). In LR analysis, after adjusting for multiple cofounders, LHR remained an independent factor for the presence of MetS among men (OR: 1.254; 95% CI: 1.202-1.308; p < 0.001) and women (OR: 1.393; 95% CI: 1.340-1.448; p < 0.001). HCHR also remained an independent factor for the presence of MetS only in women (OR: 1.058; 95% CI: 1.043-1.073; p < 0.001). ROC curve analysis showed that LHR had the higher AUC for predicting MetS in both men (AUC: 0.627; 95% CI: 0.611-0.643; p < 0.001) and women (AUC: 0.683; 95% CI: 0.670, 0.696; p < 0.001).

CONCLUSION

This suggests that among both genders, the LHR as an inexpensive and easy-to-access marker has a better diagnostic performance and could be a promising alternative to the traditional expensive inflammatory markers such as hs-CRP for the evaluation of inflammation in patients with MetS.

Hesperidin Supplementation Improves Altered PON -1, LDL Oxidation, Inflammatory Response and Hepatic Function in an Experimental Rat Model of Hyperlipidemia

In this study, we have examined the effect of hesperidin on rats fed on an experimental high-fat diet. Male Wistar rats were given a high-fat diet orally for one month for developing an HFD (High fat- diet) model. Rats were also supplemented with hesperidin (100 mg/kg body weight) for one month. We determined serum LDL (Low-density lipoprotein) oxidation, Paraoxonase-1 (PON-1) activity, and histopathological profile of the liver. Inflammatory cytokines levels were also measured in serum. HFD induced significant changes in LDL oxidation and PON-1 activity. Liver tissue histopathology and gene expression of inflammatory markers (Il-6(Interleukin-6), TNF- alpha (Tumor necrosis factor alpha), NF-KB (Nuclear factor kappa B) show that significant changes occur in the hyperlipidemic model of rats. We also show that hesperidin can effectively improve plasma antioxidant, LDL oxidation, and inflammatory cytokine expression in rats already subjected to hyperlipidemic stress. We conclude that hesperidin may protect the liver from oxidative stress by improving hepatic function.

Novel bioactive lipids enhanced HDL-mediated cholesterol efflux from macrophages through the ABCA1 receptor pathway

High-density lipoprotein (HDL) has traditionally been acknowledged as "good cholesterol" owing to its significant association with a decreased risk of atherosclerosis. This association is primarily attributed to HDL's direct involvement in cholesterol efflux capacity, which plays a pivotal role in reverse cholesterol transport. A novel active compound from Nannochloropsis microalgae termed lyso-DGTS, a lipid that contains EPA fatty acids, was previously isolated and found to increase paraoxonase 1 activity and enhance HDL-mediated cholesterol efflux and HDL-induced endothelial nitric oxide release. Here, the effect of different lyso-DGTS derivatives and analogs on HDL-mediated cholesterol efflux from macrophages was examined, and the mechanism was explored. Structure-activity relationships were established to characterize the essential lipid moieties responsible for HDL-mediated cholesterol efflux from macrophages. Lyso-DGTS, 1-carboxy-N-N-N-trimethyl-3-oleamidopropan-1-aminium, and lyso-platelet-activating factor increased HDL-mediated cholesterol efflux from macrophages dose-dependently, mainly via the ABCA1-mediated cholesterol efflux pathway. The effect of lyso-DGTS derivatives and analogs on the surface polarity of HDL was examined using the Laurdan generalized polarization (GP) assay. A reverse Pearson linear regression was obtained between Laurdan GP values and HDL-mediated cholesterol efflux. Because the incorporation of bioactive lipids into the surface phospholipid layer of HDL leads to a decrease in Laurdan GP, these bioactive lipids may induce lower phospholipid ordering and greater free space on the HDL particle surface, thereby enhancing apolipoprotein A1 binding to the ABCA1 receptor and improving ABCA1 cholesterol-mediated efflux. Our findings suggest a beneficial effect of lyso-DGTS and its bioactive lipid derivatives on increasing HDL-mediated cholesterol efflux activity from macrophages, which may impact atherosclerosis attenuation.

Serum uric acid to high-density lipoprotein ratio as a novel indicator of inflammation is correlated with the presence and severity of metabolic syndrome: A large-scale study

INTRODUCTION

We investigated the association of serum uric acid to high-density lipoprotein ratio (UHR) with the presence and severity of metabolic syndrome (MetS) among MASHAD cohort participants.

METHODS

In this cross-sectional study, according to International Diabetes Federation criteria, the cohort participants were divided into MetS (+) and MetS (-) groups. MetS (+) were classified into Group 1 (those with 3 MetS criteria), Group 2 (those with 4 MetS criteria) and Group 3 (those with 5 MetS criteria). UHR was compared among the groups.

RESULTS

Data related to 9637 subjects including 3824 MetS (+) and 5813 MetS (-) were analysed. The mean UHR was significantly higher (p < .001) in the MetS (+) group compared with the MetS (-) group. UHR increased as the MetS severity increased (p < .001). ROC analysis revealed that UHR greater than 9.5% has 89.07% sensitivity and 77.03% specificity in differentiating MetS (-) from MetS (+) subjects.

CONCLUSION

Among MASHAD cohort study participants, a significant association between UHR and MetS was found. Furthermore, there is an increase in UHR as the severity of MetS increases. Registration number of MASHAD cohort study: 85134.

Therapeutic Potential and Predictive Pharmaceutical Modeling of Stilbenes in Cannabis sativa

Cannabis sativa is a plant used for recreational and therapeutic purposes; however, many of the secondary metabolites in the plant have not been thoroughly investigated. Stilbenes are a class of compounds with demonstrated anti-inflammatory and antioxidant properties and are present in cannabis. Many stilbenes present in cannabis have been investigated for their therapeutic effects. Fourteen stilbenes have been identified to be present in cannabis, all of which are structurally dihydrostilbenoids, with half possessing a prenylated moiety. The stilbenes summarized in this analysis show varying degrees of therapeutic benefits ranging from anti-inflammatory, antiviral, and anti-cancer to antioxidant effects. Many of the identified stilbenes have been researched to a limited extent for potential health benefits. In addition, predictive in silico modeling was performed on the fourteen identified cannabis-derived stilbenes. This modeling provides prospective activity, pharmacokinetic, metabolism, and permeability data, setting the groundwork for further investigation into these poorly characterized compounds.

Relationship between High-density Lipoprotein Cholesterol and Insulin Resistance in Non-diabetic Chronic Kidney Disease Patients

Insulin resistance is linked to cardiovascular disease (CVD), even in non-diabetic patients. Therefore, insulin resistance contributes to the development of CVDs, which are the most important cause of morbidity and mortality in chronic kidney disease (CKD) and patients receiving dialysis replacement therapy. Furthermore, CKD greatly affects the enzyme activities responsible for the metabolism of high-density lipoprotein (HDL), causing an abnormal composition and function of HDL, which results in the loss of the anti-inflammatory effect of HDL and its protective effect against CVD. The study aimed to find the relationship between HDL-C, inflammation, and insulin resistance in nondiabetic CKD patients undergoing different modalities of treatment. This prospective cross-sectional comparative study included 80 subjects divided into the control group (20 healthy participants), Group 1 (15 predialysis CKD patients on conservative treatment), Group 2 (10 peritoneal dialysis patients), and Group 3 (35 hemodialysis patients). A full history, medical examination, and a laboratory investigation were carried out on all subjects from June 2018 to June 2019. The patient groups had significantly lower HDL and higher serum insulin than the control group. HDL was negatively correlated with the Homeostatic Model Assessment of Insulin Resistance. There was a strong negative association between HDL and insulin resistance in CKD patients. Therefore, lifestyle modifications and dyslipidemia treatment in CKD might help to prevent cardiovascular events even in nondiabetic nonobese CKD patients.

Very low HDL levels: clinical assessment and management

In individuals with very low high-density lipoprotein (HDL-C) cholesterol, such as Tangier disease, LCAT deficiency, and familial hypoalphalipoproteinemia, there is an increased risk of premature atherosclerosis. However, analyzes based on comparisons of populations with small variations in HDL-C mediated by polygenic alterations do not confirm these findings, suggesting that there is an indirect association or heterogeneity in the pathophysiological mechanisms related to the reduction of HDL-C. Trials that evaluated some of the HDL functions demonstrate a more robust degree of association between the HDL system and atherosclerotic risk, but as they were not designed to modify lipoprotein functionality, there is insufficient data to establish a causal relationship. We currently have randomized clinical trials of therapies that increase HDL-C concentration by various mechanisms, and this HDL-C elevation has not independently demonstrated a reduction in the risk of cardiovascular events. Therefore, this evidence shows that (a) measuring HDL-C as a way of estimating HDL-related atheroprotective system function is insufficient and (b) we still do not know how to increase cardiovascular protection with therapies aimed at modifying HDL metabolism. This leads us to a greater effort to understand the mechanisms of molecular action and cellular interaction of HDL, completely abandoning the traditional view focused on the plasma concentration of HDL-C. In this review, we will detail this new understanding and the new horizon for using the HDL system to mitigate residual atherosclerotic risk.

Atypical functions of xenobiotic receptors in lipid and glucose metabolism

Xenobiotic receptors are traditionally defined as xenobiotic chemical-sensing receptors, the activation of which transcriptionally regulates the expression of enzymes and transporters involved in the metabolism and disposition of xenobiotics. Emerging evidence suggests that "xenobiotic receptors" also have diverse endobiotic functions, including their effects on lipid metabolism and energy metabolism. Dyslipidemia is a major risk factor for cardiovascular disease, diabetes, obesity, metabolic syndrome, stroke, nonalcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH). Understanding the molecular mechanism by which transcriptional factors, including the xenobiotic receptors, regulate lipid homeostasis will help to develop preventive and therapeutic approaches. This review describes recent advances in our understanding the atypical roles of three xenobiotic receptors: aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), and constitutive androstane receptor (CAR), in metabolic disorders, with a particular focus on their effects on lipid and glucose metabolism. Collectively, the literatures suggest the potential values of AhR, PXR and CAR as therapeutic targets for the treatment of NAFLD, NASH, obesity and diabetes, and cardiovascular diseases.

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.

Cardiac Mitochondria Dysfunction in Dyslipidemic Mice

Dyslipidemia triggers many severe pathologies, including atherosclerosis and chronic inflammation. Several lines of evidence, including our studies, have suggested direct effects of dyslipidemia on cardiac energy metabolism, but details of these effects are not clear. This study aimed to investigate how mild dyslipidemia affects cardiac mitochondria function and vascular nucleotide metabolism. The analyses were performed in 3- and 6-month-old knock-out mice for low-density lipoprotein receptor (Ldlr−/−) and compared to wild-type C57Bl/6J mice (WT). Cardiac isolated mitochondria function was analyzed using Seahorse metabolic flux analyzer. The mechanical function of the heart was measured using echocardiography. The levels of fusion, fission, and mitochondrial biogenesis proteins were determined by ELISA kits, while the cardiac intracellular nucleotide concentration and vascular pattern of nucleotide metabolism ecto-enzymes were analyzed using reverse-phase high-performance liquid chromatography. We revealed the downregulation of mitochondrial complex I, together with a decreased activity of citrate synthase (CS), reduced levels of nuclear respiratory factor 1 and mitochondrial fission 1 protein, as well as lower intracellular adenosine and guanosine triphosphates’ pool in the hearts of 6-month Ldlr−/− mice vs. age-matched WT. The analysis of vascular ecto-enzyme pattern revealed decreased rate of extracellular adenosine monophosphate hydrolysis and increased ecto-adenosine deaminase activity (eADA) in 6-month Ldlr−/− vs. WT mice. No changes were observed in echocardiography parameters in both age groups of Ldlr−/− mice. Younger hyperlipidemic mice revealed no differences in cardiac mitochondria function, CS activity, intracellular nucleotides, mitochondrial biogenesis, and dynamics but exhibited minor changes in vascular eADA activity vs. WT. This study revealed that dysfunction of cardiac mitochondria develops during prolonged mild hyperlipidemia at the time point corresponding to the formation of early vascular alterations.

HDL Composition, Heart Failure, and Its Comorbidities

Although research on high-density lipoprotein (HDL) has historically focused on atherosclerotic coronary disease, there exists untapped potential of HDL biology for the treatment of heart failure. Anti-oxidant, anti-inflammatory, and endothelial protective properties of HDL could impact heart failure pathogenesis. HDL-associated proteins such as apolipoprotein A-I and M may have significant therapeutic effects on the myocardium, in part by modulating signal transduction pathways and sphingosine-1-phosphate biology. Furthermore, because heart failure is a complex syndrome characterized by multiple comorbidities, there are complex interactions between heart failure, its comorbidities, and lipoprotein homeostatic mechanisms. In this review, we will discuss the effects of heart failure and associated comorbidities on HDL, explore potential cardioprotective properties of HDL, and review novel HDL therapeutic targets in heart failure.

Simultaneous Noninvasive Detection and Therapy of Atherosclerosis Using HDL Coated Gold Nanorods

Cardiovascular disease (CVD) is a major cause of death and disability worldwide. A real need exists in the development of new, improved therapeutic methods for treating CVD, while major advances in nanotechnology have opened new avenues in this field. In this paper, we report the use of gold nanoparticles (GNPs) coated with high-density lipoprotein (HDL) (GNP-HDL) for the simultaneous detection and therapy of unstable plaques. Based on the well-known HDL cardiovascular protection, by promoting the reverse cholesterol transport (RCT), injured rat carotids, as a model for unstable plaques, were injected with the GNP-HDL. Noninvasive detection of the plaques 24 h post the GNP injection was enabled using the diffusion reflection (DR) method, indicating that the GNP-HDL particles had accumulated in the injured site. Pathology and noninvasive CT measurements proved the recovery of the injured artery treated with the GNP-HDL. The DR of the GNP-HDL presented a simple and highly sensitive method at a low cost, resulting in simultaneous specific unstable plaque diagnosis and recovery.

Abdominal obesity negatively influences key metrics of reverse cholesterol transport

Cardiometabolic risk factors increase the risk of atherosclerotic cardiovascular disease (ASCVD), but whether these metabolic anomalies affect the anti-atherogenic function of reverse cholesterol transport (RCT) is not yet clearly known. The present study aimed to delineate if the function and maturation of high density lipoprotein (HDL) particles cross-sectionally associate with surrogate markers of ASCVD in a population comprising of different degree of cardiometabolic risk. We enrolled 131 subjects and characterized cardiometabolic risk based on the IDF criteria's for metabolic syndrome (MS). In this population, cholesterol efflux capacity (CEC), Lecithin-cholesterol acyltransferase (LCAT) and ApoA-1 glycation was associated with waist circumference, abdominal visceral fat (VFA) and abdominal subcutaneous fat. In multivariate analyses, VFA was identified as a critical contributor for low CEC and LCAT. When stratified into groups based on the presence of cardiometabolic risk factors, we found a prominent reduction in CEC and LCAT as a function of the progressive increase of cardiometabolic risk from 0-2, 0-3 to 0-4/5, whereas an increase in Pre-β-HDL and ApoA-1 glycation was observed between the lowest and highest risk groups. These findings confirm the connection between MS and its predisposing conditions to an impairment of atheroprotective efflux-promoting function of HDLs. Furthermore, we have identified the bona fide pathogenically contribution of abdominal obesity to profound alterations of key metrics of RCT.

Rare variants in previously identified linkage regions associated with carotid plaque in Dominican Republic families

Carotid plaque is a subclinical measure of atherosclerosis. We have previously shown measures of carotid plaque to be heritable in a sample of 100 Dominican families and found evidence for linkage and association of common variants (CVs) on 7q36, 11p15, 14q32 and 15q23 with plaque presence. Our current study aimed to refine these regions further and identify rare variants (RVs) influencing plaque presence. Therefore, we performed targeted sequencing of the one LOD unit down region on 7q36, 11p15, 14q32 and 15q23 in 12 Dominican families with evidence for linkage to plaque presence. Gene-based RV analyses were performed using the Sequence Association Test for familial data (F-SKAT) under two filtering algorithms; 1. all exonic RVs and 2. non-synonymous RVs. Replication analyses were performed using a sample of 22 Dominican families and 556 unrelated Dominicans with Exome Array data. To identify additional non-synonymous RVs influencing plaque, we looked for co-segregation of RVs with plaque in each of the sequenced families. Our most strongly associated gene with evidence for replication was AMPD3 which showed suggestive association with plaque presence in the sequenced families (exonic RV p = 0.003, nonsynonymous RV p = 0.005) and replication families (exonic RV p = 0.04, nonsynonymous RV p = 0.02). Examination of the sequenced family pedigrees revealed two missense variants on chromosome 11 which co-segregated with plaque presence in one of our families; rs61751342 (located in DENND2B), and rs61760882 (located in RNF141). The rs61751342 missense variant is an eQTL for SCUBE2 in the atrial appendage. Notably, SCUBE2 encodes a protein which interacts with vascular endothelial growth factor (VEGF) receptor 2 to regulate VEGF-induced angiogenesis, thus providing biologic plausibility for this gene in atherosclerosis. In conclusion, using targeted sequencing of previously-identified linkage regions, we have identified suggestive evidence for the role of RVs in carotid plaque pathogenesis.

Associations of Monocytes and the Monocyte/High-Density Lipoprotein Ratio With Extracranial and Intracranial Atherosclerotic Stenosis

Background: Although the monocyte/high-density lipoprotein ratio (MHR) has been shown to be a potential marker of inflammatory of cardiovascular and cerebrovascular diseases, there are few studies on its relationships with the degree of intracranial and extracranial atherosclerotic stenosis and the stenosis distribution.

Methods: In total, 271 patients were admitted for digital subtraction angiography (DSA) examination and were classified into a non-stenosis group and a stenosis group. (1) The two groups were compared and the arteries were categorized according to the degree of intracranial or extracranial atherosclerotic stenosis (if ≥two branches were stenotic, the artery with the most severe stenosis was used). (2) Clinical baseline data and laboratory indexes of patients grouped according to stenosis location (intracranial vs. extracranial) were collected.

Results: (1) MHR × 10² [odds ratio (OR) = 1.119, p < 0.001], age (OR = 1.057, p = 0.007), and lymphocyte count (OR = 0.273, p = 0.002) significantly affected the presence of cerebral atherosclerotic stenosis, with an MHR area of 0.82 under the receiver operating characteristic (ROC) curve (AUC) and an optimal diagnostic value of 0.486. Analyses of the moderate, mild, and severe stenosis groups showed that MHR × 10² (OR = 1.07, p < 0.001) significantly affected the severity of stenosis in patients. (2) In the analysis of stenosis at different sites, the rate of extracranial artery stenosis in patients who smoked (OR = 3.86, p = 0.023) and had a reduced lymphocyte level (OR = 0.202, p = 0.001) was remarkably greater than that in patients who smoked (OR = 3.86, p = 0.023). With increasing age, the rate of extracranial artery stenosis raised sharply. With the increase in the MHR level, the stenosis rate of each group was highly greater than that of the non-stenosis group.

Conclusion: The MHR has a predictive value for the diagnosis of extracranial and intracranial atherosclerotic stenosis and is correlated with the degree and distribution of stenosis.

Trial Registration: Clinical Medical Research Center Project of Qinghai Province (2017-SF-L1). Qinghai Provincial Health Commission Project (Grant #2020-wjzdx-29).

Modulation of Bile Acid Metabolism to Improve Plasma Lipid and Lipoprotein Profiles

New drugs targeting bile acid metabolism are currently being evaluated in clinical studies for their potential to treat cholestatic liver diseases, non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Changes in bile acid metabolism, however, translate into an alteration of plasma cholesterol and triglyceride concentrations, which may also affect cardiovascular outcomes in such patients. This review attempts to gain insight into this matter and improve our understanding of the interactions between bile acid and lipid metabolism. Bile acid sequestrants (BAS), which bind bile acids in the intestine and promote their faecal excretion, have long been used in the clinic to reduce LDL cholesterol and, thereby, atherosclerotic cardiovascular disease (ASCVD) risk. However, BAS modestly but consistently increase plasma triglycerides, which is considered a causal risk factor for ASCVD. Like BAS, inhibitors of the apical sodium-dependent bile acid transporter (ASBTi’s) reduce intestinal bile acid absorption. ASBTi’s show effects that are quite similar to those obtained with BAS, which is anticipated when considering that accelerated faecal loss of bile acids is compensated by an increased hepatic synthesis of bile acids from cholesterol. Oppositely, treatment with farnesoid X receptor agonists, resulting in inhibition of bile acid synthesis, appears to be associated with increased LDL cholesterol. In conclusion, the increasing efforts to employ drugs that intervene in bile acid metabolism and signalling pathways for the treatment of metabolic diseases such as NAFLD warrants reinforcing interactions between the bile acid and lipid and lipoprotein research fields. This review may be considered as the first step in this process.

Genetics and regulation of HDL metabolism

The inverse association between plasma HDL cholesterol (HDL-C) levels and risk for cardiovascular disease (CVD) has been demonstrated by numerous epidemiological studies. However, efforts to reduce CVD risk by pharmaceutically manipulating HDL-C levels failed and refused the HDL hypothesis. HDL-C levels in the general population are highly heterogeneous and are determined by a combination of genetic and environmental factors. Insights into the causes of HDL-C heterogeneity came from the study of monogenic HDL deficiency syndromes but also from genome wide association and Μendelian randomization studies which revealed the contribution of a large number of loci to low or high HDL-C cases in the general or in restricted ethnic populations. Furthermore, HDL-C levels in the plasma are under the control of transcription factor families acting primarily in the liver including members of the hormone nuclear receptors (PPARs, LXRs, HNF-4) and forkhead box proteins (FOXO1-4) and activating transcription factors (ATFs). The effects of certain lipid lowering drugs used today are based on the modulation of the activity of specific members of these transcription factors. During the past decade, the roles of small or long non-coding RNAs acting post-transcriptionally on the expression of HDL genes have emerged and provided novel insights into HDL regulation and new opportunities for therapeutic interventions. In the present review we summarize recent progress made in the genetics and the regulation (transcriptional and post-transcriptional) of HDL metabolism.

Cholesterol Control for Subclinical Coronary Atherosclerosis in Subjects Without Indication for Statin Therapy

Low-risk individuals still experience adverse cardiac events. We sought to evaluate long-term cardiac events and predictors for subclinical coronary atherosclerosis in subjects without indication for statin therapy. We analyzed 3,272 individuals without indication for statin therapy who voluntarily underwent coronary computed tomography angiography as part of a general health examination. A cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, or late coronary revascularization. The prevalence of normal coronary arteries, nonobstructive coronary artery disease (CAD) (diameter stenosis < 50%), and obstructive CAD (diameter stenosis ≥50%) was 2,338 (71.5%), 809 (24.7%), and 125 (3.8%), respectively. During the follow-up period (median 5.3 [interquartile range, 4.3-6.3] years), the 6-year event-free survival rates were 99.2%±0.2% in subjects with normal coronary arteries, 98.2%±0.6% in those with nonobstructive CAD, and 90.2%±2.7% in those with obstructive CAD (log-rank p < 0.001). Multivariable regression analysis showed that low-density lipoprotein cholesterol (LDL-C, odds ratio [OR]: 1.012; 95% confidence interval (CI): 1.005-1.019) and high-density lipoprotein cholesterol (HDL-C, OR: 0.968; 95% CI: 0.952-0.984) levels were associated with subclinical obstructive CAD, together with age (OR: 1.080; 95% CI: 1.040-1.121) and male sex (OR: 3.102; 95% CI: 1.866-5.155) (all p < 0.05). In conclusion, LDL-C and HDL-C are significantly associated with the presence of subclinical obstructive CAD with a worse prognosis in subjects without indication for statin therapy. These findings suggest that stricter control of LDL-C and HDL-C levels may be necessary for primary prevention even in a relatively low-risk population.

Successful Genetic Screening and Creating Awareness of Familial Hypercholesterolemia and Other Heritable Dyslipidemias in the Netherlands

The genetic screening program for familial hypercholesterolemia (FH) in the Netherlands, which was embraced by the Dutch Ministry of Health from 1994 to 2014, has led to twenty years of identification of at least 1500 FH cases per year. Although funding by the government was terminated in 2014, the approach had proven its effectiveness and had built the foundation for the development of more sophisticated diagnostic tools, clinical collaborations, and new molecular-based treatments for FH patients. As such, the community was driven to continue the program, insurance companies were convinced to collaborate, and multiple approaches were launched to find new index cases with FH. Additionally, the screening was extended, now also including other heritable dyslipidemias. For this purpose, a diagnostic next-generation sequencing (NGS) panel was developed, which not only comprised the culprit LDLR, APOB, and PCSK9 genes, but also 24 other genes that are causally associated with genetic dyslipidemias. Moreover, the NGS technique enabled further optimization by including pharmacogenomic genes in the panel. Using such a panel, more patients that are prone to cardiovascular diseases are being identified nowadays and receive more personalized treatment. Moreover, the NGS output teaches us more and more about the dyslipidemic landscape that is less straightforward than we originally thought. Still, continuous progress is being made that underlines the strength of genetics in dyslipidemia, such as discovery of alternative genomic pathogenic mechanisms of disease development and polygenic contribution.

Unraveling the Complexity of HDL Remodeling: On the Hunt to Restore HDL Quality

Increasing evidence has cast doubt over the HDL-cholesterol hypothesis. The complexity of the HDL particle and its proven susceptibility to remodel has paved the way for intense molecular investigation. This state-of-the-art review discusses the molecular changes in HDL particles that help to explain the failure of large clinical trials intending to interfere with HDL metabolism, and details the chemical modifications and compositional changes in HDL-forming components, as well as miRNA cargo, that render HDL particles ineffective. Finally, the paper discusses the challenges that need to be overcome to shed a light of hope on HDL-targeted approaches.

Potential Contribution of Short Chain Fatty Acids to Hepatic Apolipoprotein A-I Production

Apolipoprotein A-I (ApoA-I) is the major protein of high density lipoprotein (HDL) particles and has a crucial role in reverse cholesterol transport (RCT). It has been postulated that elevating production of de novo ApoA-I might translate into the formation of new functional HDL particles that could lower cardiovascular disease (CVD) risk via RCT. During inflammation, serum ApoA-I concentrations are reduced, which contributes to the development of dysfunctional HDL particles as Serum Amyloid A (SAA) overtakes the position of ApoA-I within the HDL particles. Therefore, instead of elevating serum HDL cholesterol concentrations, rescuing lower serum ApoA-I concentrations could be beneficial in both normal and inflamed conditions. Several nutritional compounds, amongst others short chain fatty acids (SCFAs), have shown their capacity to modulate hepatic lipoprotein metabolism. In this review we provide an overview of HDL and more specific ApoA-I metabolism, SCFAs physiology and the current knowledge regarding the influence of SCFAs on ApoA-I expression and synthesis in human liver cells. We conclude that the current evidence regarding the effect of SCFAs on ApoA-I transcription and secretion is promising, however there is a need to investigate which dietary fibres could lead to increased SCFAs formation and consequent elevated ApoA-I concentrations.

Sex and Racial Differences in High-Density Lipoprotein Levels in Acute Coronary Syndromes

BACKGROUND

This study aimed to assess sex and racial differences related to high-density lipoprotein cholesterol (HDL-C) levels in those presenting with acute coronary syndromes (ACS).

METHODS

Records from patients with ACS presenting to the Emergency Department of University of Florida Hospital Jacksonville from 2009 to 2012, were reviewed. Detailed medical history was obtained. HDL-C levels were measured within 72 h of presentation. Pearson chi-square and Wilcoxon rank sum tests were used to compare groups in univariate analysis. Analysis of variance was performed to determine independent predictors of higher HDL-C levels using variable selection.

RESULTS

Of 2400 patients screened, 614 (382 men and 232 women) met inclusion criteria. Hypertension, chronic kidney disease or prior CAD history was similar between sexes and races. Women were more likely to be older (62.4 vs 58.4 years), diabetic (56.5 vs 36.5%) and have higher body mass index (31.2 vs 30.1 kg/m2). Blacks were more likely to be diabetic (50.3 vs 41.3%). After adjusting for all clinical markers, women and blacks along with absence of CAD or diabetes, were significantly associated with higher HDL-C levels.

CONCLUSIONS

High HDL-C levels (> 40 mg/dL), considered cardio-protective, were seen in women and blacks with ACS more often than in men and whites. Significant differences in HDL-C levels between sexes were seen in whites but not in blacks. Relevance and quality of HDL-C levels in racial groups need further study as this may have important implications in the interpretation of current guidelines.

Post-traumatic stress disorder and its association with stroke and stroke risk factors: A literature review

Stroke is a major cause of mortality and disability globally that has multiple risk factors. A risk factor that has recently gained more attention is post-traumatic stress disorder (PTSD). Literature searches were carried out for updated PTSD information and for the relationship between PTSD and stroke. The review was divided into two sections, one exploring PTSD as an independent risk factor for stroke, with a second concentrating on PTSD's influence on stroke risk factors. The study presents accumulating evidence that shows traumatic stress predicts stroke and is also linked to many major stroke risk factors. The review contributes knowledge to stroke aetiology and acts as a reference for understanding the relationship between PTSD and stroke. The information presented indicates that screening and identification of traumatic experience would be beneficial for directing stroke patients to appropriate psychological and lifestyle interventions. In doing so, the burden of stroke may be reduced worldwide.

High Density Lipoproteins and Diabetes

Epidemiological studies have established that a high plasma high density lipoprotein cholesterol (HDL-C) level is associated with reduced cardiovascular risk. However, recent randomised clinical trials of interventions that increase HDL-C levels have failed to establish a causal basis for this relationship. This has led to a shift in HDL research efforts towards developing strategies that improve the cardioprotective functions of HDLs, rather than simply increasing HDL-C levels. These efforts are also leading to the discovery of novel HDL functions that are unrelated to cardiovascular disease. One of the most recently identified functions of HDLs is their potent antidiabetic properties. The antidiabetic functions of HDLs, and recent key advances in this area are the subject of this review. Given that all forms of diabetes are increasing at an alarming rate globally, there is a clear unmet need to identify and develop new approaches that will complement existing therapies and reduce disease progression as well as reverse established disease. Exploration of a potential role for HDLs and their constituent lipids and apolipoproteins in this area is clearly warranted. This review highlights focus areas that have yet to be investigated and potential strategies for exploiting the antidiabetic functions of HDLs.

Vegan Diet Health Benefits in Metabolic Syndrome

Plant-based diets (PBDs) are increasingly consumed by the Italian population and around the world. In particular, among PBDs, the vegan diet is a food pattern characterized by the exclusion of all animal-origin foods. What drives people to adopt this model are mainly ethical, health and environmental reasons. A vegan diet, if well-balanced and varied, can help in achieving and maintaining an optimal state of health. However, this nutritional approach, if not well-balanced, can cause deficiencies in proteins, ω-3 fatty acids, iron, vitamin D and calcium, zinc, iodine and, above all, vitamin B12. Oral food supplements especially fortified foods are recommended in these cases to restore the nutritional deficiencies. A vegan diet generally reduces the risk of developing chronic non-communicable degenerative diseases, such as metabolic syndrome (MetS) and, in addition, requires fewer natural resources for food production than an omnivorous diet. The aim of this review is to analyze the possible impact of the vegan diet on MetS onset and its treatment.

Pediatric Lipid Disorders

Current scientific evidence has proven that atherosclerosis is a process that begins in childhood and tracks into adulthood, likely culminating in adverse cardiovascular events such as coronary artery disease, peripheral artery disease, and stroke. In addition, the obesity epidemic and increasing awareness of genetic lipid disorders has made the understanding and management of lipid disorders necessary for pediatricians. Childhood offers a unique opportunity for preventing, modifying, or eliminating risk factors and, in doing so, reversing or slowing the process of atherosclerosis. In general, management involves targeted lifestyle interventions such as strict dietary changes and increases in physical activity. In some circumstances, pharmacotherapy, even in childhood, is warranted. [Pediatr Ann. 2021;50(3):e105-e112.].

Comparative effects of ethanol leaf and stem bark extracts of Irvingia gabonensis (BUSH MANGO) on sodium arsenite-induced lipid profile perturbtions in wistar rats

Background

Exposure to arsenic orchestrates a myriad of noxious health effects, including cancer. Different parts ofIrvingia gabonensisare used as herbal remedies in traditional medicine. In this study, the comparative effects of the ethanol leaf (ELEIG) and stem bark extracts (ESEIG) ofIrvingia gabonensison sodium arsenite (SA)-induced lipid profile disturbances in Wistar rats were investigated.

Methods

Fifty five Wistar rats weighing between 100 g and 179 g were distributed into eleven groups (n=5). Group 1 (control) received feed and water ad libitum. Group 2 received SA at a dose of 4.1 mg/kg body weight (kgbw) for 14 days. Groups 3–11 were treated with the extracts with or without SA. Treatment was done by oral intubation for 14 days. Serum concentrations of total cholesterol (TC), triacylglycerol (TAG), high density lipoprotein cholesterol (HDL-c), low density lipoprotein cholesterol (LDL-c), very low density lipoprotein cholesterol (VLDL-c), total lipids (TL) and atherogenic index of plasma (AIP) were used to determine the lipid profile effects of the extracts.

Results

Exposure to SA caused significant (p˂ 0.05) increases in all assayed parameters, relative to control. Post-treatment and simultaneous treatment with ELEIG and ESEIG mitigated the effects of SA. In addition, ELEIG alone at various doses produced results comparable with control values. However, ESEIG alone caused significant (p˂ 0.05) increases in all assayed parameters, relative to control.

Conclusion

These results show that ELEIG and ESEIG ameliorate SA-induced lipid profile disturbances in Wistar rats. However, long-term administration of ESEIG alone may be discouraged.

High-Density Lipoprotein Modifications: A Pathological Consequence or Cause of Disease Progression?

High-density lipoprotein (HDL) is well-known for its cardioprotective effects, as it possesses anti-inflammatory, anti-oxidative, anti-thrombotic, and cytoprotective properties. Traditionally, studies and therapeutic approaches have focused on raising HDL cholesterol levels. Recently, it became evident that, not HDL cholesterol, but HDL composition and functionality, is probably a more fruitful target. In disorders, such as chronic kidney disease or cardiovascular diseases, it has been observed that HDL is modified and becomes dysfunctional. There are different modification that can occur, such as serum amyloid, an enrichment and oxidation, carbamylation, and glycation of key proteins. Additionally, the composition of HDL can be affected by changes to enzymes such as cholesterol ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT), and phospholipid transfer protein (PLTP) or by modification to other important components. This review will highlight some main modifications to HDL and discuss whether these modifications are purely a consequential result of pathology or are actually involved in the pathology itself and have a causal role. Therefore, HDL composition may present a molecular target for the amelioration of certain diseases, but more information is needed to determine to what extent HDL modifications play a causal role in disease development.

Effects of fatty liver on the size and composition of high-density lipoprotein cholesterol subpopulations in adolescents with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an emerging disease in the pediatric population. The association between T2DM and non-alcoholic fatty liver disease (NAFLD) has been described. Recent evidence suggests that sizes and composition of high-density lipoprotein (HDL) may be more important that HDL-C levels in predicting coronary heart disease. There is not data regarding the HDL subclasses distribution and composition in T2DM youths with NAFLD.

METHODS

This cross-sectional study included 47 adolescents with T2DM and 23 non-diabetic controls of both sexes aged 10 to 18 years. The presence of NAFLD was determined estimated proton density fat fraction (PDFF) by magnetic resonance by spectroscopy. We compared the HDL subclasses distribution (HDL2b, HDL2a, HDL3a HDL3b and HDL3c) and the HDL chemical composition (total protein, triglyceride, phospholipid, cholesteryl esters, and free cholesterol) between the groups of adolescents with T2DM and the control group.

RESULTS

Patients with T2DM and NAFLD had a significantly lower proportion HDL2b (P = .040) and a higher proportion of HDL3c (P = .035); higher proportion of TG (P = .032) and a lower CE (P = .002) and FC (P < .001). A negative association was observed between PDFF and the percentages of HDL2b (r² = -0.341, P = .004) and the average particle size (r² = -0.327, P = .05), and a positive association with HDL3c subpopulations (r² = 0.327, P = .015); about composition inside HDL particle, a positive association with PDFF and the TG (r² = 0.299, P = .013) and negative with CE (r² = -0.265, P = .030).

CONCLUSIONS

In adolescents diagnosed with T2DM, the presence of NAFLD is associated with abnormalities in the distribution of HDL subpopulations and the lipid composition of HDL particles.

Trimethylamine N-oxide and the reverse cholesterol transport in cardiovascular disease: a cross-sectional study

The early atherosclerotic lesions develop by the accumulation of arterial foam cells derived mainly from cholesterol-loaded macrophages. Therefore, cholesterol and cholesteryl ester transfer protein (CETP) have been considered as causative in atherosclerosis. Moreover, recent studies indicate the role of trimethylamine N-oxide (TMAO) in development of cardiovascular disease (CVD). The current study aimed to investigate the association between TMAO and CETP polymorphisms (rs12720922 and rs247616), previously identified as a genetic determinant of circulating CETP, in a population of coronary artery disease (CAD) patients (n = 394) and control subjects (n = 153). We also considered age, sex, trimethylamine (TMA) levels and glomerular filtration rate (GFR) as other factors that can potentially play a role in this complex picture. We found no association of TMAO with genetically determined CETP in a population of CAD patients and control subjects. Moreover, we noticed no differences between CAD patients and control subjects in plasma TMAO levels. On the contrary, lower levels of TMA in CAD patients respect to controls were observed. Our results indicated a significant correlation between GFR and TMAO, but not TMA. The debate whether TMAO can be a harmful, diagnostic or protective marker in CVD needs to be continued.

Identification and characterization of a rare variant in apolipoprotein A-IV, p.(V336M), and evaluation of HDL functionality in a Greek cohort with extreme HDL cholesterol levels

High-Density Lipoprotein cholesterol (HDL-C) levels do not correlate well with Coronary Artery Disease (CAD) risk, while HDL functionality affects atherogenesis and is a better prognostic marker for CAD. Often, the extreme HDL-C levels have a multigenic origin. Here, we searched for single-nucleotide polymorphisms (SNPs) in ten genes of HDL metabolism in a Greek cohort with very low (<10th percentile, n = 13) or very high (>90th percentile, n = 21) HDL-C. We also evaluated the association between HDL-C levels, HDL functionality (anti-oxidant capacity) and CAD in the subjects of this cohort. Individuals with low HDL-C levels had higher triglyceride levels, lower apoA-I levels, decreased HDL anti-oxidant capacity and higher incidence of CAD compared with individuals with control or high HDL-C levels. With next generation sequencing we identified 18 exonic SNPs in 6 genes of HDL metabolism and for selected amino acid changes we performed computer-aided structural analysis and modeling. A previously uncharacterized rare apolipoprotein A-IV variant, apoA-IV [V336M], present in a subject with low HDL-C (14 mg/dL) and CAD, was expressed in recombinant form and structurally and functionally characterized. ApoA-IV [V336M] had similar α-helical content to WT apoA-IV but displayed a small thermodynamic stabilization by chemical unfolding analysis. ApoA-IV [V336M] was able to associate with phospholipids but presented reduced kinetics compared to WT apoA-IV. Overall, we identified a rare apoA-IV variant in a subject with low HDL levels and CAD with altered biophysical and phospholipid binding properties and showed that subjects with very low HDL-C presented with HDL dysfunction and higher incidence of CAD in a Greek cohort.

Carotid artery intima-media thickness, HDL cholesterol levels, and gender associated with poor visual acuity in patients with branch retinal artery occlusion

PURPOSE

To investigate factors associated with poor visual acuity (VA) in branch retinal artery occlusion (BRAO).

METHODS

This was a retrospective cross-sectional study of 72 eyes with BRAO of 72 patients. For statistical comparison, we divided the patients into worse-VA (decimal VA < 0.5) and better-VA (decimal VA > = 0.5) groups. We examined the association of clinical findings, including blood biochemical test data and carotid artery ultrasound parameters, with poor VA.

RESULTS

Median age, hematocrit, hemoglobin and high-density lipoprotein (HDL) differed significantly between the groups (P = 0.018, P < 0.01, P < 0.01, and P = 0.025). There was a tendency towards higher median IMT-Bmax in the worse-VA group (worse-VA vs. better-VA: 2.70 mm vs. 1.60 mm, P = 0.152). Spearman's rank correlation test revealed that logMAR VA was significantly correlated to IMT-Bmax (rs = 0.31, P < 0.01) and IMT-Cmax (rs = 0.24, P = 0.035). Furthermore, logMAR VA was significantly correlated to HDL level (rs = -0.33, P < 0.01). Multivariate logistic regression analysis revealed that IMT-Bmax (odds ratio [OR] = 2.70, P = 0.049), HDL level (OR = 0.91, P = 0.032), and female gender (OR = 15.63, P = 0.032) were independently associated with worse VA in BRAO.

CONCLUSIONS

We found that increased IMT-Bmax, decreased HDL, and female sex were associated with poor VA in BRAO patients. Our findings might suggest novel risk factors for visual dysfunction in BRAO and may provide new insights into the pathomechanisms underlying BRAO.

HDL cholesterol is associated with PBMC expression of genes involved in HDL metabolism and atherogenesis

Background

To reveal the association of plasma level of high density lipoprotein cholesterol (HDL-C) level with the transcript level of annotated genes in peripheral blood mononuclear cells (PBMC) and involved in HDL metabolism and atherogenesis at the absence of morphologically evident coronary stenosis.

Methods

Transcript levels of 63 genes in PBMC from 38 male patients 40-60 years without coronary atherosclerosis with widely varied HDL-C level were measured. The protein interactions were analyzed with STRING database.

Results

Among 22 HDL-related genes, the transcript levels for 10 genes (ABCA1, BMP1, CUBN, HDLBP, LCAT, LDLR, PRKACB, PRKACG, SCARB1 and ZDHHC8) negatively correlated with HDL-C, while positively for APOA1 gene. Among 41 atherosclerosis-prone genes, the transcript levels for 11 genes (CSF1R, CSF2RB, IL18R1, ITGAM, ITGB3, PRKCQ, SREBF1, TLR5, TLR8, TNFRSF1A and TNFRSF1B) negatively correlated with HDL-C only, not with LDL-C and plasma TG. The protein products efficiently interacted within each cluster while only two intersection nodes existed between clusters.

Conclusions

Coordinate regulation of cholesterol influx and efflux in PBMC in atherosclerosis-free subjects with widely varied HDL-C level is suggested. The decreased synthesis and transport of cholesteryl ester to the liver may contribute to hyperalphalipoproteinemia. HDL-C increase is associated with the decrease of expression of innate immunity and inflammation genes. Visualization of 22 responder genes is suggested to be useful in the validation of HDL functionality and atherogenesis even at the absence of morphologically evident coronary stenosis.

Association between Egg Consumption and Cholesterol Concentration: A Systematic Review and Meta-analysis of Randomized Controlled Trials

The association of egg consumption and serum cholesterol concentrations in healthy people has been discussed for a long time. In this study, we aimed to explore association of egg consumption with on low-density lipoprotein cholesterol (LDL-c) and high-density lipoprotein cholesterol (HDL-c) concentrations and the LDL-c/HDL-c ratio through meta-analysis. This systematic review only included randomized controlled trials (RCTs) investigating egg consumption in healthy populations without combination therapy. We extracted mean and standard deviation for LDL-c/HDL-c ratio, LDL-c/HDL-c. The extracted data were pooled in a random-effects model and were presented as mean difference (MD) with 95% confidence interval (CI). Moreover, subgroup analyses were conducted for understanding effects of more egg consumption (MEC) on different intervention periods, egg-consumption levels, classification of responders. Overall, 17 RCTs met the eligibility criteria and pooled results showed MEC group had a higher LDL-c/HDL-c ratio than the control group (MD = 0.14, p = 0.001, I² = 25%). The MEC group also had higher LDL-c than the control group (MD = 8.14, p < 0.0001, I² = 18%). Moreover, for the subset of intervention over two months, the MEC group seemed to have a larger effect size than the subset of intervention within two months. This synthesis, the largest meta-analysis on this topic, shows the impact of egg consumption on lipid profiles among healthy subjects. Notably, longer time with MEC may lead to higher LDL-c/HDL-c ratio and LDL-c. However, RCTs with long tern follow-up are needed to guarantee the association between egg consumption and human health.

Lipid efflux mechanisms, relation to disease and potential therapeutic aspects

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

Novel Invasive and Noninvasive Cardiac-Specific Biomarkers in Obesity and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of fatality and disability worldwide regardless of gender. Obesity has reached epidemic proportions in population across different regions. According to epidemiological studies, CVD risk markers in childhood obesity are one of the significant risk factors for adulthood CVD, but have received disproportionally little attention. This review has examined the evidence for the presence of traditional cardiac biomarkers (nonspecific; lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, creatine kinase, myoglobulin, glycogen phosphorylase isoenzyme BB, myosin light chains, ST2, and ischemia-modified albumin) and novel emerging cardiac-specific biomarkers (cardiac troponins, natriuretic peptides, heart-type fatty acid-binding protein, and miRNAs). Besides, noninvasive anatomical and electrophysiological markers (carotid intima-media thickness, coronary artery calcification, and heart rate variability) in CVDs and obesity are also discussed. Modifiable and nonmodifiable risk factors associated with metabolic syndrome in the progression of CVD, such as obesity, diabetes, hypertension, dyslipidemia, oxidative stress, inflammation, and adipocytokines are also outlined. These underlying prognostic risk factors predict the onset of future microvascular and macrovascular complications. The understanding of invasive and noninvasive cardiac-specific biomarkers and the risk factors may yield valuable insights into the pathophysiology and prevention of CVD in a high-risk obese population at an early stage.

Interaction between adipocytes and high-density lipoprotein:new insights into the mechanism of obesity-induced dyslipidemia and atherosclerosis

Obesity is the most common nutritional disorder worldwide and is associated with dyslipidemia and atherosclerotic cardiovascular disease. The hallmark of dyslipidemia in obesity is low high density lipoprotein (HDL) cholesterol (HDL-C) levels. Moreover, the quality of HDL is also changed in the obese setting. However, there are still some disputes on the explanations for this phenomenon. There is increasing evidence that adipose tissue, as an energy storage tissue, participates in several metabolism activities, such as hormone secretion and cholesterol efflux. It can influence overall reverse cholesterol transport and plasma HDL-C level. In obesity individuals, the changes in morphology and function of adipose tissue affect plasma HDL-C levels and HDL function, thus, adipose tissue should be the main target for the treatment of HDL metabolism in obesity. In this review, we will summarize the cross-talk between adipocytes and HDL related to cardiovascular disease and focus on the new insights of the potential mechanism underlying obesity and HDL dysfunction.

Exercise Training at Maximal Fat Oxidation Intensity for Overweight or Obese Older Women: A Randomized Study

The purpose was to study the therapeutic effects of 12 weeks of supervised exercise training at maximal fat oxidation intensity (FATmax) on body composition, lipid profile, cardiovascular function, and physical fitness in overweight or obese older women. Thirty women (64.2 ± 5.1 years old; BMI 27.1 ± 2.3 kg/m²; body fat 41.3 ± 4.6%) were randomly allocated into the Exercise or Control groups. Participants in the Exercise group were trained at their individualized FATmax intensity (aerobic training), three days/week for one hour/day for 12 weeks. The Exercise group had significantly decreased body mass, BMI, fat mass, visceral trunk fat, and diastolic blood pressure. Furthermore, there were significant increases in high-density lipoprotein-cholesterol, predicted VO₂max, left ventricular ejection fraction, and sit-and-reach performance. There were no changes in the measured variables of the Control group. These outcomes indicate that FATmax is an effective exercise intensity to improve body composition and functional capacity for older women with overweight or obesity.

Coronary artery calcification in middle-aged women with premature ovarian insufficiency

OBJECTIVE

Women with premature ovarian insufficiency (POI) enter menopause before age 40. Early menopause was associated with increased risk for coronary artery disease (CAD), death from cardiovascular disease and all-cause mortality. We compared the prevalence of CAD between middle-aged women on average 10 years following the initial POI diagnosis, with a population-based cohort.

DESIGN

Cross-sectional case-control study.

PARTICIPANTS

Women from two Dutch University Medical Centers above 45 years of age previously diagnosed with POI (n = 98) were selected and compared with age- and race-matched controls from the Multi-Ethnic Study of Atherosclerosis (MESA).

MEASUREMENTS

The primary outcome was detectable coronary artery calcium (CAC) determined by coronary computed tomography (CCT).

RESULTS

Women with POI had significantly higher blood pressure, cholesterol and glucose, despite lower BMI compared to controls. Similar proportions of detectable CAC (CAC score >0 Agatston Units) were observed in women with POI and controls (POI n = 16 (16%), controls n = 52 (18%), P = 0.40 and P_adj  = 0.93). In women with POI separately, we were not able to identify associations between CVD risk factors and CAC. The following CVD risk factors in controls were positively associated with CAC: age, diabetes mellitus, hypertension and LDL cholesterol. HRT use was negatively associated with CAC in controls.

CONCLUSIONS

The presence of CAC did not differ significantly in women with POI around 50 years of age, compared to an age- and race-matched control group. We observe no increased calcified coronary disease in POI patients, despite the presence of unfavourable cardiovascular risk factors in these women.

Genetics, Dyslipidemia, and Cardiovascular Disease: New Insights

PURPOSE OF REVIEW

The cardiovascular (CV) risk related to lipid disorders is well established and is based on a robust body of evidence from well-designed randomized clinical trials, as well as prospective observational studies. In the last two decades, significant advances have been made in understanding the genetic basis of dyslipidemias. The present review is intended as a comprehensive discussion of current knowledge about the genetics and pathophysiology of disorders that predispose to dyslipidemia. We also focus on issues related to statins and the proprotein convertase subtilisin/kexin type 9 (PCSK9) and some of its polymorphisms, as well as new cholesterol-lowering medications, including PCSK9 inhibitors.

RECENT FINDING

Cholesterol is essential for the proper functioning of several body systems. However, dyslipidemia-especially elevated low-density lipoprotein (LDL-c) and triglyceride levels, as well as reduced lipoprotein lipase activity-is associated with an increased risk of coronary artery disease (CAD). High-density lipoprotein (HDL-c), however, seems to play a role as a risk marker rather than as a causal factor of the disease, as suggested by Mendelian randomization studies. Several polymorphisms in the lipoprotein lipase locus have been described and are associated with variations in the activity of this enzyme, producing high concentrations of triglycerides and increased risk of CAD. Dyslipidemia, especially increased LDL-c and triglyceride levels, continues to play a significant role in CV risk. The combination of genetic testing and counseling is important in the management of patients with dyslipidemia of genetic etiology. Strategies focused on primary prevention can offer an opportunity to reduce CV events.

Dysfunctional high density lipoprotein failed to rescue the function of oxidized low density lipoprotein-treated endothelial progenitor cells: a novel index for the prediction of HDL functionality

Lipid metabolic disorders play critical roles in atherogenesis. Traditionally, it has been suggested that reduced high density lipoprotein (HDL) levels might be an important morbidity indicator for cardiovascular diseases. Therefore, it has been argued that therapeutically raising HDL levels may reduce atherogenesis in patients with dyslipidemia. However, recent clinical trials to elevate serum HDL levels by pharmacologic approaches failed to demonstrate clinical efficacy. Thus, to investigate the functionality of HDL and to explore the possible clinical relevance as well as to define an effective indicator that can represent HDL function may provide another key and reference to disclose the clinical treatment of dyslipidemia. We analyzed the association between the data of dichlorofluorescein assay (assay the functionality of HDL), the effect of HDL on oxidized low density lipoprotein (oxLDL)-stimulated endothelial progenitor cells (EPCs) in vitro, levels of circulating EPCs, and ex vitro EPC colony forming units of each case, we defined the indicator (relative HDL index (RHDL index) = dichlorofluorescein assay result of each subject/dichlorofluorescein assay reading of our young healthy controls) that may represent functionality of HDL. HDL from healthy adults protected oxLDL-treated EPCs by modulating p38 mitogen-activated protein kinase and Rho activation and by promoting nitric oxide production. HDL from subject with RHDL index ≧2 also failed to restore the functionality of oxLDL-treated EPCs via cell-signaling pathways in vitro. The RHDL index significantly correlated with patients' circulating EPC number or EPC colony forming units ex vivo. In conclusions, we explored the RHDL index as a score to predict a patient's EPC functions in vivo and ex vitro.