High density lipoproteins: Measurement techniques and potential biomarkers of cardiovascular risk

HDL abnormalities in type 2 diabetes: Clinical implications

Atherosclerotic cardiovascular disease (ASCVD) represents the primary cause of mortality among patients with Type 2 Diabetes Mellitus (T2DM). In this population, High-Density Lipoprotein (HDL) particles exhibit abnormalities in number, composition, and function, culminating in diminished anti-atherosclerotic capabilities despite normal HDL cholesterol (HDL-C) concentrations. Hyperglycemic conditions contribute to these alterations in HDL kinetics, composition, and function, causing T2DM patients' HDL particles to exhibit decreased concentrations of diverse lipid species and proteins. Treatment of hyperglycemia has the potential to correct abnormal HDL particle attributes in T2DM; however, pharmacological interventions, including metformin and thiazolidinediones, yield inconsistent outcomes with respect to HDL-C concentrations and functionality. Despite numerous attempts with diverse drugs, pharmacologically augmenting HDL-C levels has not resulted in clinical benefits in mitigating ASCVD risk. In contrast, reducing Low Density Lipoprotein cholesterol (LDL-C) via statins and ezetimibe has demonstrated significant efficacy in curtailing CVD risk among T2DM individuals. Promising results have been observed in animal models and early-phase trials utilizing recombinant HDL and Lecitin Cholesterol Acyl Transferase (LCAT) -enhancing agents, but the evaluation of their efficacy and safety in large-scale clinical trials is ongoing. While aberrant HDL metabolism constitutes a prevalent aspect of dyslipidemia in T2DM, HDL cholesterol concentrations and composition no longer offer valuable insights for informing therapeutic decisions. Nevertheless, HDL metabolism remains a critical research area in T2DM, necessitating further investigation to elucidate the role of HDL particles in the development of diabetes-associated complications.

High-density lipoprotein metrics during midlife and future subclinical atherosclerosis in women: the SWAN HDL study

OBJECTIVE

The clinical utility of high-density lipoprotein cholesterol (HDL-C) in risk classification is limited, especially in midlife women. Novel metrics of HDL may better reflect this risk. We clustered a comprehensive profile of HDL metrics into favorable and unfavorable clusters and assessed how these two clusters are related to future subclinical atherosclerosis (carotid intima media thickness [cIMT], interadventitial diameter [IAD], and carotid plaque presence) in midlife women.

METHODS

Four hundred sixty-one women (baseline age: 50.4 [2.7] years; 272 White, 137 Black, 52 Chinese) from the Study of Women's Health Across the Nation HDL ancillary study who had baseline measures of HDL cholesterol efflux capacity (HDL-CEC), lipid contents (HDL-phospholipids [HDL-PL] and HDL triglycerides [HDL-Tg]), and HDL particle (HDL-P) distribution and size, followed by carotid ultrasound (average 12.9 [SD: 2.6] years later), were included. Using latent cluster analysis, women were clustered into a favorable (high HDL-CEC, HDL-PL, large and medium HDL-P, less HDL-Tg and small HDL-P, larger size) or an unfavorable HDL cluster (low HDL-CEC, HDL-PL, large and medium HDL-P, more HDL-Tg, and small HDL-P, smaller size) and then linked to future subclinical atherosclerosis using linear or logistic regression.

RESULTS

The favorable HDL cluster was associated with lower cIMT, IAD, and odds of carotid plaque presence. These associations were attenuated by body mass index, except in Chinese women where the association with cIMT persisted (0.72 [0.63, 0.83]).

CONCLUSIONS

The association between favorable HDL clusters and a better postmenopausal subclinical atherosclerosis profile is largely explained by body mass index; however, racial/ethnic differences may exist.

Cholesterol transport and beyond: Illuminating the versatile functions of HDL apolipoproteins through structural insights and functional implications

High-density lipoproteins (HDLs) play a vital role in lipid metabolism and cardiovascular health, as they are intricately involved in cholesterol transport and inflammation modulation. The proteome of HDL particles is indeed complex and distinct from other components in the bloodstream. Proteomics studies have identified nearly 285 different proteins associated with HDL; however, this review focuses more on the 15 or so traditionally named "apo" lipoproteins. Important lipid metabolizing enzymes closely working with the apolipoproteins are also discussed. Apolipoproteins stand out for their integral role in HDL stability, structure, function, and metabolism. The unique structure and functions of each apolipoprotein influence important processes such as inflammation regulation and lipid metabolism. These interactions also shape the stability and performance of HDL particles. HDLs apolipoproteins have multifaceted roles beyond cardiovascular diseases (CVDs) and are involved in various physiological processes and disease states. Therefore, a detailed exploration of these apolipoproteins can offer valuable insights into potential diagnostic markers and therapeutic targets. This comprehensive review article aims to provide an in-depth understanding of HDL apolipoproteins, highlighting their distinct structures, functions, and contributions to various physiological processes. Exploiting this knowledge holds great potential for improving HDL function, enhancing cholesterol efflux, and modulating inflammatory processes, ultimately benefiting individuals by limiting the risks associated with CVDs and other inflammation-based pathologies. Understanding the nature of all 15 apolipoproteins expands our knowledge of HDL metabolism, sheds light on their pathological implications, and paves the way for advancements in the diagnosis, prevention, and treatment of lipid and inflammatory-related disorders.

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.

Oxylipin transport by lipoprotein particles and its functional implications for cardiometabolic and neurological disorders

Lipoprotein metabolism is critical to inflammation. While the periphery and central nervous system (CNS) have separate yet connected lipoprotein systems, impaired lipoprotein metabolism is implicated in both cardiometabolic and neurological disorders. Despite the substantial investigation into the composition, structure and function of lipoproteins, the lipoprotein oxylipin profiles, their influence on lipoprotein functions, and their potential biological implications are unclear. Lipoproteins carry most of the circulating oxylipins. Importantly, lipoprotein-mediated oxylipin transport allows for endocrine signaling by these lipid mediators, long considered to have only autocrine and paracrine functions. Alterations in plasma lipoprotein oxylipin composition can directly impact inflammatory responses of lipoprotein metabolizing cells. Similar investigations of CNS lipoprotein oxylipins are non-existent to date. However, as APOE4 is associated with Alzheimer's disease-related microglia dysfunction and oxylipin dysregulation, ApoE4-dependent lipoprotein oxylipin modulation in neurological pathologies is suggested. Such investigations are crucial to bridge knowledge gaps linking oxylipin- and lipoprotein-related disorders in both periphery and CNS. Here, after providing a summary of existent literatures on lipoprotein oxylipin analysis methods, we emphasize the importance of lipoproteins in oxylipin transport and argue that understanding the compartmentalization and distribution of lipoprotein oxylipins may fundamentally alter our consideration of the roles of lipoprotein in cardiometabolic and neurological disorders.

Measurement of cholesterol levels of lipoprotein subclasses in human serum using anion-exchange high-performance liquid chromatography with a linear concentration gradient of sodium perchlorate

BACKGROUND

Relationships between the subclasses of high-density lipoprotein (HDL) or low-density lipoprotein (LDL) and the risk of atherosclerotic cardiovascular disease have been studied, and using various methods, such as ultracentrifugation, electrophoresis, and nuclear magnetic resonance, for analysing lipoprotein subclasses. We established a method for HDL and LDL subclasses using anion-exchange high-performance liquid chromatography (AEX-HPLC) with a linear concentration gradient of sodium perchlorate (NaClO4).

METHOD

In the AEX-HPLC, the subclasses of HDL and LDL were separated, and detected using a post-column reactor with an enzymatic cholesterol reagent, that contained cholesterol esterase, cholesterol oxidase, and peroxidase as major ingredients. LDL subclasses were divided based on the absolute value of first-derivative chromatogram.

RESULT

Three HDL subclasses, HDL-P1, HDL-P2, and HDL-P3, and three LDL subclasses, LDL-P1, LDL-P2, and LDL-P3, were separated by AEX-HPLC, and detected in order. The major components of HDL-P2 and HDL-P3 were HDL3 and HDL2, respectively. The linearity was determined for each lipoprotein subclass. The coefficients of variation of cholesterol concentration of the subclasses for within-day assay (n = 10) and between-day assay (n = 10) ranged between 3.08-8.94% and 4.52-9.97%, respectively. Cholesterol levels in HDL-P1 of diabetic patients were positively correlated with oxidized LDL levels (r = 0.409, p = 0.002). Moreover, cholesterol levels in LDL-P2 and LDL-P3 were positively correlated with oxidized LDL levels (r = 0.393, p = 0.004 and r = 0.561, p < 0.001, respectively).

CONCLUSION

AEX-HPLC may be highly suitable as an assay to clinically assess lipoprotein subclasses.

Hypertensive Disorders of Pregnancy: Assessing the Significance of Lp(a) and ApoB Concentrations in a Romanian Cohort

Background: This research delves into the association between altered lipid profiles and hypertensive disorders of pregnancy (HDP), shedding light on cardiovascular implications in maternal health. Methods: A cohort of 83 pregnant women was studied, with 48.19% diagnosed with HDP. This investigation primarily focused on Apolipoprotein B (ApoB) and Lipoprotein(a) (Lp(a)) as indicators of cardiovascular health. A comparative examination was conducted to determine discrepancies in the ApoB and Lp(a) levels between standard pregnancies and those presenting with HDP. Results: Significant elevations in ApoB (p value = 0.0486) and Lp(a) (p value < 0.0001) levels were observed in pregnant women with HDP compared to their counterparts with typical pregnancies. The pronounced link between heightened ApoB and Lp(a) concentrations and HDP persisted, even considering pregnancy's distinct physiological conditions. Conclusions: Our research accentuates the crucial role of early detection and specialized handling of cardiovascular risks in expectant mothers, especially those predisposed to HDP. The study indicates ApoB and Lp(a)'s potential as reliable markers for gauging cardiovascular threats during gestation. Furthermore, our findings suggest an integrative care approach and guidance for pregnant women, aspiring to enhance cardiovascular health in the postpartum phase.

Assessment of Inflammatory Hematological Ratios (NLR, PLR, MLR, LMR and Monocyte/HDL-Cholesterol Ratio) in Acute Myocardial Infarction and Particularities in Young Patients

Cardiovascular disease, particularly coronary artery disease (CAD), remains a predominant cause of mortality globally. Factors such as atherosclerosis and inflammation play significant roles in the pathogenesis of CAD. The nexus between inflammation and CAD is underscored by the role of immune cells, such as neutrophils, lymphocytes, monocytes, and macrophages. These cells orchestrate the inflammatory process, a core component in the initiation and progression of atherosclerosis. The activation of these pathways and the subsequent lipid, fibrous element, and calcification accumulation can result in vessel narrowing. Hematological parameters derived from routine blood tests offer insights into the underlying inflammatory state. Recent studies have highlighted the potential of inflammatory hematological ratios, such as the neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, monocyte/lymphocyte ratio and lymphocyte/monocyte ratio. These parameters are not only accessible and cost-effective but also mirror the degree of systemic inflammation. Several studies have indicated a correlation between these markers and the severity, prognosis, and presence of CAD. Despite the burgeoning interest in the relationship between inflammatory markers and CAD, there remains a paucity of data exploring these parameters in young patients with acute myocardial infarction. Such data could offer valuable insights into the unique pathophysiology of early-onset CAD and improve risk assessment and predictive strategies.

The role of atherogenic lipoproteins in diabetes: Molecular aspects and clinical significance

Dyslipidaemia plays a prominent role in the genesis of atherosclerotic plaque and the increased cardiovascular risk in diabetes. Macrophages readily take up atherogenic lipoproteins, transforming into foam cells and amplifying vascular damage in the presence of endothelial dysfunction. We discuss the importance of distinct lipoprotein subclasses in atherogenic diabetic dyslipidaemia as well as the effects of novel anti-diabetic agents on lipoprotein fractions and ultimately on cardiovascular risk prevention. In patients with diabetes, lipid abnormalities should be aggressively identified and treated in conjunction with therapeutical agents used to prevent cardiovascular disease. The use of drugs that improve diabetic dyslipidaemia plays a prominent role in conferring cardiovascular benefit in individuals with diabetes.

Role of combined use of mean platelet volume-to-lymphocyte ratio and monocyte to high-density lipoprotein cholesterol ratio in predicting patients with acute myocardial infarction

BACKGROUND

Atherosclerosis and thrombosis play important roles in the pathophysiology of acute coronary syndrome, with platelet activation and inflammation as the key and initiative factors. Recently mean platelet volume-to-lymphocyte ratio (MPVLR) and monocyte to high-density lipoprotein cholesterol ratio (MHR) have emerged as new prognostic indicators of cardiovascular diseases. However, the predicting effect of the combination of MPVLR and MHR in myocardial infarction has not been reported.

OBJECTIVE

The aim of this study was to investigate the usefulness of combination of MPVLR and MHR in predicting patients with AMI.

METHODS

375 patients who had chest pain or stuffiness were retrospectively enrolled in this study. According to the results of coronary angiography and cardiac troponin, patients were divided into AMI group (n = 284) and control group (n = 91). MPVLR, MHR, Gensini score and Grace score were calculated.

RESULTS

MPVLR and MHR were significantly higher in AMI group than that in control group (6.47 (4.70-9.58) VS 4.88 (3.82-6.44), 13.56 (8.44-19.01) VS 9.14 (7.00-10.86), P < 0.001, respectively). Meanwhile, both were positively correlated with Gensini score and Grace score. Patients with a high level of MPVLR or MHR had an increased risk for AMI (odds ratio (OR) = 1.2, 95% confidence interval (CI) 1.1-1.4, OR = 1.2, 95% CI 1.2-1.3). Combination of MPVLR and MHR identified a greater ROC area than its individual parameters (P < 0.001).

CONCLUSION

Both MPVLR and MHR are independent predictors of AMI. Combination of MPVLR and MHR had higher predicting value in AMI, and thus appears to be a new risk factor and biomarker in the evaluation of risk and severity of atherosclerosis in AMI.

HDL Function and Size in Patients with On-Target LDL Plasma Levels and a First-Onset ACS

Patients admitted for acute coronary syndrome (ACS) usually have high cardiovascular risk scores with low levels of high-density lipoprotein cholesterol (HDL-C) and high low-density lipoprotein cholesterol (LDL-C) levels. Here, we investigated the role of lipoprotein functionality as well as particle number and size in patients with a first-onset ACS with on-target LDL-C levels. Ninety-seven patients with chest pain and first-onset ACS with LDL-C levels of 100 ± 4 mg/dL and non-HDL-C levels of 128 ± 4.0 mg/dL were included in the study. Patients were categorized as ACS and non-ACS after all diagnostic tests were performed (electrocardiogram, echocardiogram, troponin levels and angiography) on admission. HDL-C and LDL-C functionality and particle number/size by nuclear magnetic resonance (NMR) were blindly investigated. A group of matched healthy volunteers (n = 31) was included as a reference for these novel laboratory variables. LDL susceptibility to oxidation was higher and HDL-antioxidant capacity lower in the ACS patients than in the non-ACS individuals. ACS patients had lower HDL-C and Apolipoprotein A-I levels than non-ACS patients despite the same prevalence of classical cardiovascular risk factors. Cholesterol efflux potential was impaired only in the ACS patients. ACS-STEMI (Acute Coronary Syndrome—ST-segment-elevation myocardial infarction) patients, had a larger HDL particle diameter than non-ACS individuals (8.4 ± 0.02 vs. 8.3 ± 0.02 and, ANOVA test, p = 0.004). In conclusion, patients admitted for chest pain with a first-onset ACS and on-target lipid levels had impaired lipoprotein functionality and NMR measured larger HDL particles. This study shows the relevance of HDL functionality rather than HDL-C concentration in ACS patients.

HDL-Based Therapy: Vascular Protection at All Stages

It is known that lipid metabolism disorders are involved in a wide range of pathologies. These pathologies include cardiovascular, metabolic, neurodegenerative diseases, and even cancer. All these diseases lead to serious health consequences, which makes it impossible to ignore them. Unfortunately, these diseases most often have a complex pathogenesis, which makes it difficult to study them and, in particular, diagnose and treat them. HDL is an important part of lipid metabolism, performing many functions under normal conditions. One of such functions is the maintaining of the reverse cholesterol transport. These functions are also implicated in pathology development. Thus, HDL contributes to vascular protection, which has been demonstrated in various conditions: Alzheimer’s disease, atherosclerosis, etc. Many studies have shown that serum levels of HDL cholesterol correlate negatively with CV risk. With these data, HDL-C is a promising therapeutic target. In this manuscript, we reviewed HDL-based therapeutic strategies that are currently being used or may be developed soon.

Lipids at the Nexus between Cerebrovascular Disease and Vascular Dementia: The Impact of HDL-Cholesterol and Ceramides

Cerebrovascular diseases and the subsequent brain hypoperfusion are at the basis of vascular dementia. Dyslipidemia, marked by an increase in circulating levels of triglycerides and LDL-cholesterol and a parallel decrease in HDL-cholesterol, in turn, is pivotal in promoting atherosclerosis which represents a common feature of cardiovascular and cerebrovascular diseases. In this regard, HDL-cholesterol has traditionally been considered as being protective from a cardiovascular and a cerebrovascular prospective. However, emerging evidence suggests that their quality and functionality play a more prominent role than their circulating levels in shaping cardiovascular health and possibly cognitive function. Furthermore, the quality of lipids embedded in circulating lipoproteins represents another key discriminant in modulating cardiovascular disease, with ceramides being proposed as a novel risk factor for atherosclerosis. This review highlights the role of HDL lipoprotein and ceramides in cerebrovascular diseases and the repercussion on vascular dementia. Additionally, the manuscript provides an up-to-date picture of the impact of saturated and omega-3 fatty acids on HDL circulating levels, functionality and ceramide metabolism.

Monocyte to HDL and Neutrophil to HDL Ratios as Potential Ischemic Stroke Prognostic Biomarkers

Ischemic stroke (IS) exhibits significant heterogeneity in terms of etiology and pathophysiology. Several recent studies highlight the significance of inflammation in the onset and progression of IS. White blood cell subtypes, such as neutrophils and monocytes, participate in the inflammatory response in various ways. On the other hand, high-density lipoproteins (HDL) exhibit substantial anti-inflammatory and antioxidant actions. Consequently, novel inflammatory blood biomarkers have emerged, such as neutrophil to HDL ratio (NHR) and monocyte to HDL ratio (MHR). Literature research of two databases (MEDLINE and Scopus) was conducted to identify all relevant studies published between 1 January 2012 and 30 November 2022 dealing with NHR and MHR as biomarkers for IS prognosis. Only full-text articles published in the English language were included. Thirteen articles have been traced and are included in the present review. Our findings highlight the utility of NHR and MHR as novel stroke prognostic biomarkers, the widespread application, and the calculation of which, along with their inexpensive cost, make their clinical application extremely promising.

Quantifying PON1 on HDL with nanoparticle-gated electrokinetic membrane sensor for accurate cardiovascular risk assessment

Cardiovascular disease-related deaths (one-third of global deaths) can be reduced with a simple screening test for better biomarkers than the current lipid and lipoprotein profiles. We propose using a highly atheroprotective subset of HDL with colocalized PON1 (PON1-HDL) for superior cardiovascular risk assessment. However, direct quantification of HDL proteomic subclasses are complicated by the peroxides/antioxidants associated with HDL interfering with redox reactions in enzymatic calorimetric and electrochemical immunoassays. Hence, we developed an enzyme-free Nanoparticle-Gated Electrokinetic Membrane Sensor (NGEMS) platform for quantification of PON1-HDL in plasma within 60 min, with a sub-picomolar limit of detection, 3-4 log dynamic range and without needing sample pretreatment or individual-sample calibration. Using NGEMS, we report our study on human plasma PON1-HDL as a cardiovascular risk marker with AUC~0.99 significantly outperforming others (AUC~0.6-0.8), including cholesterol/triglycerides tests. Validation for a larger cohort can establish PON1-HDL as a biomarker that can potentially reshape cardiovascular landscape.

Changes in the size and electrophoretic mobility of HDL subpopulation particles in chronic kidney disease

BACKGROUND

High-density lipoprotein (HDL) is a heterogeneous group of particles with anti-atherogenic properties whose metabolism is alterated in chronic kidney disease (CKD). The aim of this study was to evaluate the particle size and mobility of HDL subpopulations in non-dialysis CKD patients.

METHODS

The study involved 42 non-dialysis CKD patients (stages 3a-4) and 18 control subjects. HDL was separated by non-denaturing two-dimensional polyacrylamide gradient gel electrophoresis (2D-PAGGE) and eight HDL subpopulations; preβ1, preβ2a-c, and α1-4 were distinguished. The size and electrophoretic mobility of HDL subpopulation particles were compared between the groups, and a regression analysis was conducted.

RESULTS

In CKD patients, the mean sizes of α-HDL and preβ2-HDL particles were significantly lower compared to the control group (8.42 ± 0.32 nm vs. 8.64 ± 0.26 nm, p = 0.014; 11.45 ± 0.51 vs. 12.34 ± 0.78 nm, p = 0.003, respectively). The electrophoretic mobility of preβ2-HDL relative to α-HDL was significantly higher in CKD patients compared to the control group (Rf 0.65 ± 0.06 vs. 0.53 ± 0.10, p = 0.002). The size and mobility of HDL subpopulations correlated with eGFR values (p < 0.01). These relationships remained statistically significant after adjusting for age, gender, statin treatment, apolipoprotein AI, total cholesterol, and triglyceride levels.

DISCUSSION

CKD affects the size and mobility of HDL particles, which can be related to HDL dysfunction. The magnitude of HDL size and mobility changes depended on CKD stage and differed for individual HDL subpopulations, which indicates that some stages of HDL metabolism may be more affected by the presence of chronic kidney disease.

Treatment effect of metformin combined with atorvastatin in reducing in-stent restenosis after percutaneous coronary intervention in coronary artery disease patients with type 2 diabetic patients

To investigate the effectiveness of metformin and atorvastatin in preventing in-stent restenosis (ISR) on coronary patients with type 2 diabetes mellitus with percutaneous coronary intervention within 8 to 12 months after rapamycin-eluting stent implantation. A total of 1278 consecutive patients implanted with rapamycin-eluting stent from January 2012 to December 2019, who underwent coronary computed tomography or coronary angiography within 8 to 12 months. The patients were categorized into atorvastatin 20 mg, or atorvastatin 20 mg + metformin 1.5/d, or atorvastatin 40 mg + metformin 1.5/d groups. The clinical characteristics of the 3 groups were compared. The correlation between variables and ISR was analyzed. A total of 701 patients participated in the study. The ratio of ISR/nonstenosis (P = .039) and fasting blood sugar (P = .001) differed significantly in the 3 groups. Logistic regression showed that d, L, different therapeutic agents, and dosage groups were independent risk factors of ISR. The longer L and smaller d may increase ISR incidence with 8 to 12 months after percutaneous coronary intervention. Both metformin and atorvastatin are beneficial in reducing stent restenosis by a dose-dependent manner. An increasing dose of atorvastatin and a combination of metformin decreases the incidence of ISR in patients.

High-Density Lipoprotein and Cardiovascular Disease-Where do We Stand?

Decades of research have shown that high-density lipoprotein cholesterol (HDL-C) levels in humans are associated with atherosclerotic cardiovascular disease (ASCVD). This association is strong and coherent across populations and remains after the elimination of covariates. Animal studies show that increasing HDL particles prevent atherosclerosis, and basic work on the biology of HDL supports a strong biological plausibility for a therapeutic target. This enthusiasm is dampened by Mendelian randomization data showing that HDL-C may not be causal in ASCVD. Furthermore, drugs that increase HDL-C have largely failed to prevent or treat ASCVD.

Effect of N-3 Polyunsaturated Fatty Acids on Lipid Composition in Familial Hypercholesterolemia: A Randomized Crossover Trial

Individuals with familial hypercholesterolemia (FH) have an increased risk of cardiovascular disease. Treatment is mainly low-density lipoprotein cholesterol (LDL-C) reduction. How omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplements affect lipoproteins in FH subjects is unknown. We hypothesized that a high-dose n-3 PUFA supplement would reduce atherogenic lipoproteins and influence the high-density lipoprotein cholesterol (HDL-C) function. We performed a randomized, double-blinded crossover study with 34 genetically verified FH individuals (18−75 years, clinically stable, statin treatment > 12 months). Treatment was 4 g n-3 PUFAs (1840 mg eicosapentaenoic acid and 1520 mg docosahexaenoic acid daily) or four capsules of olive oil for three months in a crossover design with a washout period of three months. The defined outcomes were changes in triglycerides, lipoproteins, lipoprotein subfractions, apolipoproteins, and HDL-C function. After treatment with n-3 PUFAs, total cholesterol, LDL-C, and triglycerides were reduced compared to placebo (p ≤ 0.01 for all). Total HDL-C levels were unchanged, but the subfraction of large HDL-C was higher (p ≤ 0.0001) after n-3 PUFAs than after placebo, and intermediate HDL-C and small HDL-C were reduced after n-3 PUFAs compared to placebo (p = 0.02 and p ≤ 0.001, respectively). No changes were found in apolipoproteins and HDL-C function. N-3 PUFAs supplements reduced atherogenic lipoproteins in FH subjects, leaving HDL-C function unaffected.

A comparative evaluation of cardiac and neurological safety status of two commonly used oral hypoglycaemic agents in T2-DM Swiss albino mice model

Background

Diabetes mellitus (DM), along with its associated complications, including diabetic neuropathy and hyperlipidemia, has become a global concern in the last few decades. The main objective of our study is to evaluate the comparative neuro-safety status, serum plasma glucose, and lipid-lowering potential of two widely recognized antidiabetic drugs named metformin and glimepiride.

Methods

The neurological evaluation was done by open field test, hole board test, forced swimming test, dark and lighthouse test, and elevated plus maze test by employing diazepam as standard. Serum blood glucose level of streptozotocin (STZ)-induced diabetic mice was determined by glucose oxidizing method using a glucometer. Total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and very-low-density lipoprotein cholesterol (VLDL-C) levels were estimated by using the reference method where atorvastatin was used as standard.

Results

In neurological evaluation, both drugs produce almost the same anxiolytic activity in the open field test, hole board test, light and dark house test, and elevated plus maze test. However, in the forced swimming test, glimepiride produced more antidepressant activity than metformin. Glimepiride was found to remarkably reduce serum glucose and VLDL-C levels more than metformin, whereas, for other parameters, metformin takes over glimepiride sometimes took over the standard atorvastatin.

Conclusions

The results of our study indicate that both oral hypoglycaemic drugs alter the lipid index while producing some anxiolytic effects on the central nervous system. Thus, recommended to be carefully administered to patients with low BMI and might be beneficial to patients suffering from peripheral nerve function and anxiety.

Current models of apolipoprotein A-I lipidation by adenosine triphosphate binding cassette transporter A1

PURPOSE OF REVIEW

The primary cardioprotective function of high-density lipoprotein (HDL) is to remove excess cellular free cholesterol (FC) from peripheral tissues and deliver it to the liver. Here, we summarize recent research that examines apolipoprotein A-I (apoA-I) lipidation models by adenosine triphosphate binding cassette transporter A1 (ABCA1) and discuss its relevance in atherosclerotic cardiovascular disease (ASCVD).

RECENT FINDINGS

The first step in HDL formation involves the interaction between apoA-I and ABCA1, where ABCA1 mediates the removal of FC and phospholipids from lipid-laden macrophages to form discoidal nascent HDL (nHDL). However, there are currently no clear-cut systematic models that characterize HDL formation. A number of recent studies have investigated the importance of apoA-I C- and N-terminal domains required for optimal cholesterol efflux and nHDL production. Furthermore, functional ABCA1 is required for direct or indirect binding to apoA-I where ABCA1 dimer-monomer interconversion facilitates apoA-I lipidation from plasma membrane microdomains. Microparticles are also another lipid source for apoA-I solubilization into nHDL.

SUMMARY

ApoA-I and ABCA1 are key factors in macrophage-mediated cholesterol efflux and nHDL production. Understanding of the key steps in HDL formation may unlock the therapeutic potential of HDL and improve clinical management of ASCVD.

S-Nitrosylation of Paraxonase 1 (PON1) Elevates Its Hydrolytic and Antioxidant Activities

Covalent binding between nitric oxide (NO) and a protein’s free thiol group (SH) is termed protein S-nitrosylation. Protein S-nitrosylation is involved in cellular regulation mechanisms that underlie a wide range of critical functions, such as apoptosis, alteration of enzyme activities, and transcription-factor stability. Impaired protein S-nitrosylation is associated with a growing list of pathophysiological conditions, such as cardiovascular disease, multiple sclerosis, pulmonary hypertension, and sickle cell disease. The enzyme paraoxonase 1 (PON1) binds to high-density lipoprotein to provide many of its antiatherogenic properties. The enzyme has a strong antioxidant capacity, which protects fats, lipids, and lipoproteins from oxidation, in addition to breaking down oxidized fats. We investigated the effect of S-S transnitrosylation on PON1 activities. Incubation of recombinant PON1 (rePON1) with nitrosylated human serum albumin (HSA-NO) resulted in S-nitrosylation of about 70% of the rePON1, as measured by Q-TOF LC/MS. S-nitrosylation significantly increased rePON1 hydrolytic activities. It also increased rePON1’s ability to inhibit low-density lipoprotein oxidation induced by Cu²⁺. Finally, it increased the enzyme’s penetration into macrophage cells by 31%. Our findings suggest that S-nitrosylation of rePON1 improves its biological functions which may positively affect atherosclerosis disease progression.

Cholesterol Transport Dysfunction and Its Involvement in Atherogenesis

Atherosclerosis is the cause of the development of serious cardiovascular disorders, leading to disability and death. Numerous processes are involved in the pathogenesis of atherosclerosis, including inflammation, endothelial dysfunction, oxidative stress, and lipid metabolism disorders. Reverse transport of cholesterol is a mechanism presumably underlying the atheroprotective effect of high-density lipoprotein. In this review, we examined disorders of cholesterol metabolism and their possible effect on atherogenesis. We paid special attention to the reverse transport of cholesterol. Transformed cholesterol metabolism results in dyslipidemia and early atherosclerosis. Reverse cholesterol transport is an endogenous mechanism by which cells export cholesterol and maintain homeostasis. It is known that one of the main factors leading to the formation of atherosclerotic plaques on the walls of blood vessels are multiple modifications of low-density lipoprotein, and the formation of foam cells following them.

A New Look at Novel Cardiovascular Risk Biomarkers: The Role of Atherogenic Lipoproteins and Innovative Antidiabetic Therapies

The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk.

The Effect of Plant-Based Nutrition Diets on Plasma Lipids Profile—A Study Case in Romania

Diet is an important tool in managing dyslipidemic disorders, thus contributing to the prophylaxis of cardiovascular morbidity. Research has shown that a plant-based diet could have positive effects through many pathways. We conducted a study on a group of 38 plant-based individuals from Romania who have adopted the diet for at least one year. The aim of the research was to evaluate eventual changes in their lipid profile. We analyzed to what extent the values of different markers significantly changed following the dietary transition. Improvements were obtained for body mass index (BMI) and all lipid markers, with the exception of high-density lipoprotein cholesterol (HDL-C). Results showed that 75.0% of persons with elevated TGs (triglycerides) succeeded in normalizing them, as well as individuals with high low-density lipoprotein cholesterol (LDL-C) levels, where 72.7% from the borderline elevated became optimal. The total cholesterol (TC)/HDL-C ratio shifted from elevated to optimum in 78.6% of cases. Results were poor in three participants with presumed familial hypercholesterolemia, which were later successfully managed by using lipid-lowering medication. In conclusion, although dyslipidemias are only a surrogate marker for cardiovascular morbidity, the actions by which a plant-based diet can influence cardiovascular diseases are multiple, and we consider that our study confirms its positive effect.

Moderate alcohol consumption and lipoprotein subfractions: a systematic review of intervention and observational studies

CONTEXT

Moderate alcohol consumption is associated with decreased risk of cardiovascular disease (CVD) and improvement in cardiovascular risk markers, including lipoproteins and lipoprotein subfractions.

OBJECTIVE

To systematically review the relationship between moderate alcohol intake, lipoprotein subfractions, and related mechanisms.

DATA SOURCES

Following PRISMA, all human and ex vivo studies with an alcohol intake up to 60 g/d were included from 8 databases.

DATA EXTRACTION

A total of 17 478 studies were screened, and data were extracted from 37 intervention and 77 observational studies.

RESULTS

Alcohol intake was positively associated with all HDL subfractions. A few studies found lower levels of small LDLs, increased average LDL particle size, and nonlinear relationships to apolipoprotein B-containing lipoproteins. Cholesterol efflux capacity and paraoxonase activity were consistently increased. Several studies had unclear or high risk of bias, and heterogeneous laboratory methods restricted comparability between studies.

CONCLUSIONS

Up to 60 g/d alcohol can cause changes in lipoprotein subfractions and related mechanisms that could influence cardiovascular health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 98955.

Combined Intranasal Insulin/Saxagliptin/Metformin Therapies Ameliorate the Effect of Combined Oral Contraceptive- (COC-) Induced Metabolic Syndrome (MetS) with a Major Target on Glucose Metabolism in Adult Female Wistar Rats

Objective

To evaluate the effect of the chronic use of combined oral contraceptives (COCs: ethinyl estradiol and levonorgestrel) on the indices of metabolic syndrome in adult female Wistar rats and possible therapeutic management.

Materials and Methods

64 female Wistar rats received either distilled water, norethindrone (NOR), COC, intranasal insulin (INI), metformin (MET), saxagliptin (SAX), INI+MET, and INI+SAX. After 8 weeks of exposure to COC, the animals were sorted into the therapeutic groups. Several parameters were assayed for, such as body weight changes, fasting blood glucose (FBG) level, insulin levels, inflammatory cytokines, and glycated hemoglobin (Hb1Ac).

Results

The levels of FBG, insulin, and Hb1Ac were increased consequent upon COC treatment. Treatment with INI+SAX and INI+MET reduced significantly the levels of FBG and Hb1Ac; in addition, the level of insulin was significantly increased in the INI+MET groups (p ≤ 0.05). Serum lipid profile analysis showed a statistical reduction in high-density lipoprotein (HDL) level; this reduction was also significantly reversed in the INI+SAX group. Reduced catalase activity observed in the COC group was reversed in the INI+MET group (p ≤ 0.05). A nonsignificant increase in the level of TNF-α as a result of COC treatment was reversed by INI and INI+MET treatment. Liver GLUT4 and G-6-phosphate levels were significantly increased by COC treatment, and this effect was reversed by INI+SAX in both assays, respectively (p ≤ 0.01).

Conclusions

The use of MET and SAX in combination with INI has been shown to reverse some indices of MetS. This study proposes a clinical phase to backup and ascertain these preclinical findings.

High-density lipoprotein cholesterol to apolipoprotein A1 ratio and all-cause mortality among incident peritoneal dialysis patients

BACKGROUND AND AIMS

The ratio of high-density lipoprotein cholesterol to apolipoprotein A1 (HAR) is associated with all-cause mortality in nonchronic kidney disease patients, but its role in predicting all-cause mortality in patients undergoing peritoneal dialysis (PD) is still unclear. The purpose of this study was to investigate the relationship between HAR and all-cause mortality in patients with PD.

METHODS AND RESULTS

The medical records of 1199 patients with PD from November 1, 2005, to August 31, 2019, were collected retrospectively. The main outcome was defined as all-cause mortality. The HAR was divided into three groups by X-tile software. The association between HAR and all-cause mortality was evaluated by Cox models. The Kaplan-Meier method was used for the survival curve. The median follow-up period was 35 months (interquartile range: 20-57 months), with a total of 326 deaths recorded. After multiple adjustments, the risk of all-cause mortality in the high HAR group was 1.96-fold higher than that in the low HAR group (hazard ratio: 1.96; 95% CI, 1.22 to 3.15; P = 0.005). The restricted cubic splines showed that the risk of all-cause mortality increased gradually when HAR was >0.37. In the stratified analysis, a high HAR was linked to a high risk of all-cause mortality in males, patients under 55 years old, and patients without diabetes or cardiovascular disease (CVD).

CONCLUSION

This study suggests that HAR is independently related to all-cause mortality in PD patients, especially in males, patients under 55 years old, and patients without diabetes or CVD.

PoLA/CFPiP/PCS/PSLD/PSD/PSH guidelines on diagnosis and therapy of lipid disorders in Poland 2021

In Poland there are still nearly 20 million individuals with hypercholesterolaemia, most of them are unaware of their condition; that is also why only ca. 5% of patients with familial hypercholesterolaemia have been diagnosed; that is why other rare cholesterol metabolism disorders are so rarely diagnosed in Poland. Let us hope that these guidelines, being an effect of work of experts representing 6 main scientific societies, as well as the network of PoLA lipid centers being a part of the EAS lipid centers, certification of lipidologists by PoLA, or the growing number of centers for rare diseases, with a network planned by the Ministry of Health, improvements in coordinated care for patients after myocardial infarction (KOS-Zawał), reimbursement of innovative agents, as well as introduction in Poland of an effective primary prevention program, will make improvement in relation to these unmet needs in diagnostics and treatment of lipid disorders possible.

High Density Lipoproteins: Is There a Comeback as a Therapeutic Target?

Low plasma levels of High Density Lipoprotein (HDL) cholesterol (HDL-C) are associated with increased risks of atherosclerotic cardiovascular disease (ASCVD). In cell culture and animal models, HDL particles exert multiple potentially anti-atherogenic effects. However, drugs increasing HDL-C have failed to prevent cardiovascular endpoints. Mendelian Randomization studies neither found any genetic causality for the associations of HDL-C levels with differences in cardiovascular risk. Therefore, the causal role and, hence, utility as a therapeutic target of HDL has been questioned. However, the biomarker "HDL-C" as well as the interpretation of previous data has several important limitations: First, the inverse relationship of HDL-C with risk of ASCVD is neither linear nor continuous. Hence, neither the-higher-the-better strategies of previous drug developments nor previous linear cause-effect relationships assuming Mendelian randomization approaches appear appropriate. Second, most of the drugs previously tested do not target HDL metabolism specifically so that the futile trials question the clinical utility of the investigated drugs rather than the causal role of HDL in ASCVD. Third, the cholesterol of HDL measured as HDL-C neither exerts nor reports any HDL function. Comprehensive knowledge of structure-function-disease relationships of HDL particles and associated molecules will be a pre-requisite, to test them for their physiological and pathogenic relevance and exploit them for the diagnostic and therapeutic management of individuals at HDL-associated risk of ASCVD but also other diseases, for example diabetes, chronic kidney disease, infections, autoimmune and neurodegenerative diseases.

Comparability of 11 different equations for estimating LDL cholesterol on different analysers

OBJECTIVES

Low-density lipoprotein cholesterol (LDL-C) estimation is critical for risk classification, prevention and treatment of atherosclerotic cardiovascular disease (ASCVD). Predictive equations and direct LDL-C are used. We investigated the comparability between the Martin/Hopkins, Sampson, Friedewald and eight other predictive equations on two analysers, to determine whether the equation or analyser influences predicted LDL-C result.

METHODS

In two unpaired datasets, 9,995 lipid profiles were analysed by the Abbott Architect and 4,782 by the Roche Cobas analysers. Non-parametric statistics and Bland Altman plots were used to compare LDL-C.

RESULTS

On the Abbott analyser; the Martin/Hopkins, Sampson and Friedewald LDL-C were comparable (median bias ≤1.8%) over a range of 1-4.9 mmol/L. On the Roche platform, Martin/Hopkins LDL-C was comparable to Friedewald (median bias 0.3%) but not to Sampson LDL-C (median bias 25%). In patients with LDL-C <1.8 mmol/L and triglycerides (TG) ≤1.7 mmol/L, predicted LDL-C using Abbott reagents was similar between Martin/Hopkins, Sampson and Friedewald equations but not comparable using Roche reagents. Abbott reagents classified 10-20% of patients in the 1.0-1.8 mmol/L range (Martin/Hopkins 13.4%; Sampson 14.5%; Friedewald 16%; direct LDL-C 13.2%). Roche reagents classified 11-30% in the 1.0-1.8 mmol/L range (Martin/Hopkins 23%; Sampson 11%; Friedewald 25%; direct LDL-C 17%).

CONCLUSIONS

Performance of predictive equations is influenced by the choice of analyser for total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and TG. Replacement of the Friedewald equation with Martin/Hopkins estimation to improve quality of LDL-C results can be safely implemented across analysers, whereas caution is advised regarding the Sampson equation.

Isolation of HDL by sequential flotation ultracentrifugation followed by size exclusion chromatography reveals size-based enrichment of HDL-associated proteins

High-density lipoprotein (HDL) particles have multiple beneficial and cardioprotective roles, yet our understanding of their full structural and functional repertoire is limited due to challenges in separating HDL particles from contaminating plasma proteins and other lipid-carrying particles that overlap HDL in size and/or density. Here we describe a method for isolating HDL particles using a combination of sequential flotation density ultracentrifugation and fast protein liquid chromatography with a size exclusion column. Purity was visualized by polyacrylamide gel electrophoresis and verified by proteomics, while size and structural integrity were confirmed by transmission electron microscopy. This HDL isolation method can be used to isolate a high yield of purified HDL from a low starting plasma volume for functional analyses. This method also enables investigators to select their specific HDL fraction of interest: from the least inclusive but highest purity HDL fraction eluting in the middle of the HDL peak, to pooling all of the fractions to capture the breadth of HDL particles in the original plasma sample. We show that certain proteins such as lecithin cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), and clusterin (CLUS) are enriched in large HDL particles whereas proteins such as alpha-2HS-glycoprotein (A2HSG), alpha-1 antitrypsin (A1AT), and vitamin D binding protein (VDBP) are enriched or found exclusively in small HDL particles.

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.

Evaluation of dysfunctional high-density lipoprotein levels with myeloperoxidase/paraoxonase-1 ratio in rheumatoid arthritis

BACKGROUND

The aim of this study is to evaluate dysfunctional high-density lipoprotein cholesterol (HDL) by measuring myeloperoxidase (MPO)/paraoxonase 1 (PON1) ratio in patients with rheumatoid arthritis (RA) and to investigate the relationship between dysfunctional HDL and cardiovascular disease (CVD) in RA patients.

METHODS

Sixty-seven healthy individuals and 130 RA patients were included in the study. Routine lipid panels (triglyceride (TG), low-density lipoprotein cholesterol (LDL), HDL, total cholesterol (TC), PON1 and MPO levels were measured. Disease activity scores-28 (DAS28) of RA patients were calculated. Cardiological examination records of the patients were assessed to detect patients who also have CVD.

RESULTS

There were no significant differences between RA and control groups in routine lipid profiles (P > .05 for all). MPO/PON1 ratios were significantly elevated in the RA group compared with the control group (P < .001). MPO/PON1 ratios were higher in RA patients with CVD history compared with those without CVD (P < .05). MPO/PON1 ratios were correlated with DAS28 scores (rho: 0.357, P < .001).

CONCLUSION

HDL dysfunction determined by the MPO/PON1 ratio may be associated with the pathophysiology of increased CVD in RA. Thus, evaluating dysfunctional HDL levels by measuring the MPO/PON1 ratio in RA patients may allow more detailed patient follow-up, as well as the reduction of CVD events in RA patients with therapeutic agents aiming to increase the functional properties of HDL by decreasing this ratio.

Investigating the relationship between the severity of coronary artery disease and inflammatory factors of MHR, PHR, NHR, and IL-25

Background: Coronary artery disease (CAD), as a most common cause of death, is mainly caused by atherosclerosis. Due to the role of inflammation in the process of atherosclerosis, in the present study, the relationship between the severity of coronary artery disease and inflammatory factors of monocyte to HDL-C ratio (MHR), platelet-to-HDL-C ratio (PHR), neutrophil to HDL-C ratio (NHR), and IL-25 was investigated.

Methods: In this cross-sectional study, 64 patients with diagnosis of coronary artery disease who were undergoing angiography in Farshchian heart center in Hamadan were studied. For each patient, the count of monocytes, neutrophils, platelet, and HDL-C, and IL-25 were measured from their blood and serum samples. Also, demographic information, such as age, gender, diabetes, smoking, and history of hypertension, was collected using a checklist. Data were described using frequency, percent, mean, and standard deviation. Statistical analysis was performed using independent t test, Mann-Whitney, Wilcoxon, and Spearman rank correlation tests, and multiple linear regression by SPSS version 25.0 SPSS Inc). P <.05 was considered as significant.

Results: The results of this study showed that IL-25 and MHR index has a significant correlation with coronary artery disease and Gensini score (P ˂.001). The PHR index was associated with coronary artery disease. Also, qualitative variables, such as history of hypertension, history of smoking, and gender, have a significant association with the severity of coronary artery disease (P <.05).

Conclusion: Among the inflammatory markers examined, IL-25 and MHR are stronger markers for assessing the severity of coronary artery disease. Simple and available IL-25 and MHR measurements may be able to, along with common risk factors and lipid profiles, predict the amount of vascular occlusion in treatment centers as an alternative of angiography as well as screening high risk patients prone to cardiovascular disease.

HDL Dysfunctionality: Clinical Relevance of Quality Rather Than Quantity

High-density lipoproteins (HDLs) represent a class of lipoproteins very heterogeneous in structure, composition, and biological functions, which carry out reverse cholesterol transport, antioxidant, anti-inflammatory, antithrombotic, and vasodilator actions. Despite the evidence suggesting a clear inverse relationship between HDL cholesterol (HDL-c) concentration and the risk for cardiovascular disease, plasma HDL cholesterol levels do not predict the functionality and composition of HDLs. The importance of defining both the amount of cholesterol transported and lipoprotein functionality has recently been highlighted. Indeed, different clinical conditions such as obesity, diabetes mellitus type 2 (T2DM), and cardiovascular disease (CVD) can alter the HDL functionality, converting normal HDLs into dysfunctional ones, undergoing structural changes, and exhibiting proinflammatory, pro-oxidant, prothrombotic, and proapoptotic properties. The aim of the current review is to summarize the actual knowledge concerning the physical-chemical alteration of HDLs related to their functions, which have been found to be relevant in several pathological conditions associated with systemic inflammation and oxidative stress.

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

BACKGROUND

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

METHOD

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

RESULT

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

CONCLUSIONS

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

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.

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

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

Monocyte to high-density lipoprotein cholesterol ratio is associated with the presence of carotid artery disease in acute ischemic stroke

Aim: Monocyte to high-density lipoprotein cholesterol ratio (MHR) has recently emerged as a predictor of cardio-cerebrovascular diseases. Since around one-fifth of strokes are linked to atherosclerosis carotid artery, we aimed to present the relationship between carotid artery disease (CAD) and MHR value in acute ischemic stroke (AIS). Materials & methods: A total of 209 adult AIS patients analyzed. Patients divided into two groups in respect to the existence of CAD. MHR was compared between the two groups. Results: MHR with a cut off of 17.23 predicted the presence of disease in the carotid artery, with a sensitivity of 91.9% and specificity of 66.7. MHR was the independent predictor for the presence of disease in the carotid artery. Conclusion: MHR was found to be an independent predictor for the CAD in AIS. Therefore, in AIS patients with high MHR value, CAD should be examined more carefully.

Revealing the Role of High-Density Lipoprotein in Colorectal Cancer

Colorectal cancer (CRC) is a highly prevalent malignancy with multifactorial etiology, which includes metabolic alterations as contributors to disease development. Studies have shown that lipid status disorders are involved in colorectal carcinogenesis. In line with this, previous studies have also suggested that the serum high-density lipoprotein cholesterol (HDL-C) level decreases in patients with CRC, but more recently, the focus of investigations has shifted toward the exploration of qualitative properties of HDL in this malignancy. Herein, a comprehensive overview of available evidences regarding the putative role of HDL in CRC will be presented. We will analyze existing findings regarding alterations of HDL-C levels but also HDL particle structure and distribution in CRC. In addition, changes in HDL functionality in this malignancy will be discussed. Moreover, we will focus on the genetic regulation of HDL metabolism, as well as the involvement of HDL in disturbances of cholesterol trafficking in CRC. Finally, possible therapeutic implications related to HDL will be presented. Given the available evidence, future studies are needed to resolve all raised issues concerning the suggested protective role of HDL in CRC, its presumed function as a biomarker, and eventual therapeutic approaches based on HDL.

Arylesterase activity of paraoxonase 1 (PON1) on HDL3 and HDL2: Relationship with Q192R, C-108T, and L55M polymorphisms

Background

Controversy exists regarding the role of the subfractions of high-density lipoproteins (HDL₂ and HDL₃) in cardiovascular disease. The functionality of these particles, and their protective role, is due in part to the paraoxonase 1 (PON1) presence in them. The polymorphisms rs662 (Q192R, A/G), rs854560 (L55 M, T/A), and rs705379 (C-108T) of the PON1 gene have been related to enzyme activity and, with the anti-oxidative capacity of the HDL. The objective was to determine the arylesterase PON1 activity in HDL₃ and HDL₂ and its relationship with the polymorphisms mentioned, in a young population.

Methods

The polymorphisms were determined through mini-sequencing (SnaPshot). The HDL subpopulations were separated via ionic precipitation, cholesterol was measured with enzymatic methods, and PON1 activity was measured through spectrophotometry.

Results

The results show that the PON1 polymorphisms do not influence the cholesterol in the HDL. A variation between 40.02 and 43.9 mg/dL was in all the polymorphisms without significant differences. Additionally, PON1 activity in the HDL₃ subfractions was greater (62.83 ± 20 kU/L) than with HDL₂ (35.8 ± 20.8 kU/L) in the whole population and in all the polymorphisms (p < 0.001), and it was independent of the polymorphism and differential arylesterase activity in the Q192R polymorphism (QQ > QR > RR). Thus, 115.90 ± 30.7, 88.78 ± 21.3, 65.29 ± 10.2, respectively, for total HDL, with identical behavior for HDL₃ and HDL₂.

Conclusions

PON1 polymorphisms do not influence the HDL_-c, and the PON activity is greater in the HDL₃ than in the HDL₂, independent of the polymorphism, but it is necessary to delve into the functionality of these findings in different populations.

•

PON1 polymorphisms do not influence the cholesterol in the HDL subfractions.

•

PON1 arylesterase activity in the HDL₃ subfractions was greater than with HDL₂.

•

In Q192R, L55 M and C-108T polymorphisms, PON1 activity is always higher in HDL3.

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This study shows that healthy young people in Colombia have very low HDL cholesterol.

Efficacy of oral rosuvastatin intervention on HDL and its associated proteins in men with type 2 diabetes mellitus

PURPOSE

High-density lipoprotein (HDL) undergoes structural and functional modification in patients with type 2 diabetes mellitus (T2DM). There are limited data on effect of rosuvastatin on HDL-associated proteins and the antiatherogenic effects of rosuvastatin. The present study intended to study the efficacy of rosuvastatin intervention on HDL-associated proteins and its other antiatherogenic effects in men with T2DM.

METHODS

Men with T2DM on oral antidiabetic treatment, with LDL-C levels > 75 mg/dL and willing for rosuvastatin intervention (20 mg/day orally for a period of 12 weeks), were included. Fasting glucose, lipid profile were measured using standard methods. Oxidized low-density lipoprotein (oxLDL), oxidized HDL (oxHDL), paraoxonase-1 (PON-1), tumour necrosis factor-α (TNF-α) and lecithin:cholesterol acyltransferase (LCAT) in serum were measured by ELISA; serum myeloperoxidase (MPO) by spectrophotometric method and cholesterol efflux by fluorometric assay. Carotid intima-media thickness (cIMT) measurement to assess vascular health status was done using doppler.

RESULTS

Rosuvastatin produced a significant decrease (p < 0.05) in lipids (total cholesterol, triglycerides, LDL-C); oxidative stress (oxLDL, oxHDL, MPO); inflammation (TNF-α); LCAT concentration; cIMT; significant increase in antiatherogenic HDL and cholesterol efflux (p < 0.05) and no change in apoA-I levels from baseline to 12 weeks of follow-up. A decrease in MPO activity was found to be independently associated with an increase in cholesterol efflux.

CONCLUSIONS

Post intervention there is a quantitative and qualitative improvement in HDL, which helps in its reverse cholesterol transport (RCT) and antioxidant functions. Improvement in HDL functions and suppression of inflammation by rosuvastatin lead to regression in cIMT, which is beneficial in decreasing the progression of cardiovascular disease (CVD) in men with diabetes.

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 novel apoA-I mimetic peptide suppresses atherosclerosis by promoting physiological HDL function in apoE-/- mice

BACKGROUND AND PURPOSE

Apolipoprotein A-I (apoA-I) mimetic peptides (AAMPs) are short peptides that can mimic the physiological effects of apoA-I, including the suppression of atherosclerosis by reversely transporting peripheral cholesterol to the liver. As the hydrophobicity of apoA-I is considered important for its lipid transport, novel AAMPs were designed and synthesized in this study by gradually increasing the hydrophobicity of the parent peptide, and their anti-atherosclerotic effects were tested.

EXPERIMENTAL APPROACH

Seventeen new AAMPs (P1-P17) with incrementally increased hydrophobicity were designed and synthesized by replacing the amino acids 221-240 of apoA-I (VLESFKVSFLSALEEYTKKL). Their effects on cholesterol efflux were evaluated. Their cytotoxicity and haemolytic activity were also measured. The in vitro mechanism of the action of the new peptides was explored. Adult apolipoprotein E^-/- mice were used to evaluate the anti-atherosclerotic activity of the best candidate, and the mechanistic basis of its anti-atherosclerotic effects was explored.

KEY RESULTS

Seventeen new AAMPs (P1-P17) were synthesized, and their cholesterol efflux activity and cytotoxicity were closely related to their hydrophobicity. P12 (FLEKLKELLEHLKELLTKLL) was the best candidate and most strongly promoted cholesterol efflux among the non-toxic peptides (P1-P12). With its phospholipid affinity, P12 facilitated cholesterol transport through the ATP-binding cassette transporter A1. In vivo, P12 exhibited prominent anti-atherosclerotic activity via coupling with HDL.

CONCLUSION AND IMPLICATIONS

P12 featured adequate hydrophobicity, which ensured its efficient binding with cytomembrane phospholipids, cholesterol and HDL, and provided a basis for its ability to reversely transport cholesterol and treat atherosclerosis.

Could personalised risk prediction for type 2 diabetes using polygenic risk scores direct prevention, enhance diagnostics, or improve treatment?

Over the past three decades, the number of people globally with diabetes mellitus has more than doubled. It is estimated that by 2030, 439 million people will be suffering from the disease, 90-95% of whom will have type 2 diabetes (T2D). In 2017, 5 million deaths globally were attributable to T2D, placing it in the top 10 global causes of death. Because T2D is a result of both genetic and environmental factors, identification of individuals with high genetic risk can help direct early interventions to prevent progression to more serious complications. Genome-wide association studies have identified ~400 variants associated with T2D that can be used to calculate polygenic risk scores (PRS). Although PRSs are not currently more accurate than clinical predictors and do not yet predict risk with equal accuracy across all ethnic populations, they have several potential clinical uses. Here, we discuss potential usages of PRS for predicting T2D and for informing and optimising interventions. We also touch on possible health inequality risks of PRS and the feasibility of large-scale implementation of PRS in clinical practice. Before PRSs can be used as a therapeutic tool, it is important that further polygenic risk models are derived using non-European genome-wide association studies to ensure that risk prediction is accurate for all ethnic groups. Furthermore, it is essential that the ethical, social and legal implications of PRS are considered before their implementation in any context.

Cardioprotective Properties of HDL: Structural and Functional Considerations

BACKGROUND

As Mendelian Randomization (MR) studies showed no effect of variants altering HDL-cholesterol (HDL-C) levels concerning Cardiovascular Disease (CVD) and novel therapeutic interventions aiming to raise HDL-C resulted to futility, the usefulness of HDL-C is unclear.

OBJECTIVE

As the role of HDL-C is currently doubtful, it is suggested that the atheroprotective functions of HDLs can be attributed to the number of HDL particles, and their characteristics including their lipid and protein components. Scientific interest has focused on HDL function and on the causes of rendering HDL particles dysfunctional, whereas the relevance of HDL subclasses with CVD remains controversial.

METHODS

The present review discusses changes in quality as much as in quantity of HDL in pathological conditions and the connection between HDL particle concentration and cardiovascular disease and mortality. Emphasis is given to the recently available data concerning the cholesterol efflux capacity and the parameters that determine HDL functionality, as well as to recent investigations concerning the associations of HDL subclasses with cardiovascular mortality.

RESULTS

MR studies or pharmacological interventions targeting HDL-C are not in favor of the hypothesis of HDL-C levels and the relationship with CVD. The search of biomarkers that relate with HDL functionality is needed. Similarly, HDL particle size and number exhibit controversial data in the context of CVD and further studies are needed.

CONCLUSION

There is no room for the old concept of HDL as a silver bullet,as HDL-C cannot be considered a robust marker and does not reflect the importance of HDL particle size and number. Elucidation of the complex HDL system, as well as the finding of biomarkers, will allow the development of any HDL-targeted therapy.