HDL Particles Research Articles

High-Density Lipoprotein in Metabolic Disorders and Beyond: An Exciting New World Full of Challenges and Opportunities.

High-density lipoprotein (HDL) is an enigmatic member of the plasma lipid and lipoprotein transport system, best known for its ability to promote the reverse cholesterol efflux and the unloading of excess cholesterol from peripheral tissues. More recently, data in experimental mice and humans suggest that HDL may play important novel roles in other physiological processes associated with various metabolic disorders. Important parameters in the HDL functions are its apolipoprotein and lipid content, further reinforcing the principle that HDL structure defines its functionality. Thus, based on current evidence, low levels of HDL-cholesterol (HDL-C) or dysfunctional HDL particles contribute to the development of metabolic diseases such as morbid obesity, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. Interestingly, low levels of HDL-C and dysfunctional HDL particles are observed in patients with multiple myeloma and other types of cancer. Therefore, adjusting HDL-C levels within the optimal range and improving HDL particle functionality is expected to benefit such pathological conditions. The failure of previous clinical trials testing various HDL-C-raising pharmaceuticals does not preclude a significant role for HDL in the treatment of atherosclerosis and related metabolic disorders. Those trials were designed on the principle of "the more the better", ignoring the U-shape relationship between HDL-C levels and morbidity and mortality. Thus, many of these pharmaceuticals should be retested in appropriately designed clinical trials. Novel gene-editing-based pharmaceuticals aiming at altering the apolipoprotein composition of HDL are expected to revolutionize the treatment strategies, improving the functionality of dysfunctional HDL.

NMR-based metabolomic profiling identifies inflammation and muscle-related metabolites as predictors of incident type 2 diabetes mellitus beyond glucose: The Di@bet.es study

AimsThe aim of this study was to combine nuclear magnetic resonance-based metabolomics and machine learning to find a glucose-independent molecular signature associated with future type 2 diabetes mellitus development in a subgroup of individuals from the Di@bet.es study. MethodsThe study group included 145 individuals developing type 2 diabetes mellitus during the 8-year follow-up, 145 individuals matched by age, sex and BMI who did not develop diabetes during the follow-up but had equal glucose concentrations to those who did and 145 controls matched by age and sex. A metabolomic analysis of serum was performed to obtain the lipoprotein and glycoprotein profiles and 15 low molecular weight metabolites. Several machine learning-based models were trained. ResultsLogistic regression performed the best classification between individuals developing type 2 diabetes during the follow-up and glucose-matched individuals. The area under the curve was 0.628, and its 95% confidence interval was 0.510–0.746. Glycoprotein-related variables, creatinine, creatine, small HDL particles and the Johnson-Neyman intervals of the interaction of Glyc A and Glyc B were statistically significant. ConclusionsThe model highlighted a relevant contribution of inflammation (glycosylation pattern and HDL) and muscle (creatinine and creatine) in the development of type 2 diabetes as independent factors of hyperglycemia.

Isolation of recombinant apolipoprotein E4 N-terminal domain by foam fractionation

Apolipoprotein (apo) E functions in lipoprotein metabolism as a low density lipoprotein receptor ligand. ApoE is comprised of two structural domains, a 22 kDa N-terminal (NT) domain that adopts a helix bundle conformation and a 10 kDa C-terminal domain with strong lipid binding affinity. The NT domain is capable of transforming aqueous phospholipid dispersions into discoidal reconstituted high density lipoprotein (rHDL) particles. Given the utility of apoE-NT as a structural component of rHDL, expression studies were conducted. A plasmid construct encoding a pelB leader sequence fused to the N-terminus of human apoE4 (residues 1–183) was transformed into Escherichia coli. Upon expression, the fusion protein is directed to the periplasmic space where leader peptidase cleaves the pelB sequence, generating mature apoE4-NT. In shaker flask expression cultures, apoE4-NT escapes the bacteria and accumulates in the medium. In a bioreactor setting, however, apoE4-NT was found to combine with gas and liquid components in the culture medium to generate large quantities of foam. When this foam was collected in an external vessel and collapsed into a liquid foamate, analysis revealed that apoE4-NT was the sole major protein present. The product protein was further isolated by heparin affinity chromatography (60–80 mg/liter bacterial culture), shown to be active in rHDL formulation, and documented to serve as an acceptor of effluxed cellular cholesterol. Thus, foam fractionation provides a streamlined process to produce recombinant apoE4-NT for biotechnology applications.

Lipoprotein Apheresis: Current Recommendations for Treating Familial Hypercholesterolemia and Elevated Lipoprotein(a).

Familial hypercholesterolemia (FH) and hyperlipoproteinemia(a) are relatively common disorders, posing a significant health burden due to increased risk of atherosclerotic cardiovascular disease (ASCVD). Development of electronic health record-based strategies with a linkage to the genetic test results has increased awareness, detection, and control of heritable lipid disorders. This review attempts to critically examine available data to provide a summary of the current evidence for lipoprotein apheresis in FH and elevated lipoprotein(a) (Lp(a)). Availability and indications for lipoprotein apheresis vary across the globe. On average, greater than 60% of atherogenic apoB-containing lipoproteins are immediately reduced following a single procedure, translating in substantial reduction of incident ASCVD events, and preventing accelerated vascular aging. Simultaneous lipid-lowering therapy targeting low-density lipoprotein (LDL) and Lp(a) enhances the efficacy of lipoprotein apheresis. Lipoprotein apheresis alters the proteomics of the lipoprotein particles, including reduction in the concentration of the oxidized-LDL and Lp(a) particles, and proinflammatory apoE bound to HDL particles and remnant lipoproteins. Other effects attributed to lipoprotein apheresis include improvement in blood rheology, endothelial function, microvascular flow, myocardial perfusion, reduction in circulating inflammatory markers. Development of lipoprotein apheresis registries provides data on benefits, challenges, and barriers to inform pertinent healthcare policies. Lipoprotein apheresis is a safe and effective procedure for lowering cholesterol in patients with combined and isolated FH and elevated Lp(a). It reduces the burden of ASCVD and improves long-term prognosis. A team approach is required by the patient, medical staff, and healthcare provider to initiate and maintain a lipoprotein apheresis program.

Lipoprotein Particle Profiles Associated with Telomere Length and Telomerase Complex Components.

Telomere length (TL) is a well-known marker of age-related diseases. Oxidative stress and inflammation increase the rate of telomere shortening, triggering cellular senescence. Although lipoproteins could have anti-inflammatory and proinflammatory functional properties, the relationship between lipoprotein particles with TL and telomerase activity-related genes has not been investigated much. In this study, we assessed the associations of lipoprotein subfractions with telomere length, TERT, and WRAP53 expression in a total of 54 pre-diabetic subjects from the EPIRDEM study. We regressed TL, TERT, and WRAP53 on 12 lipoprotein subclasses, employing a Gaussian linear regression method with Lasso penalty to determine a lipoprotein profile associated with telomere-related parameters. The covariates included age, sex, body mass index (BMI), dyslipidemia, statin consumption, and physical activity leisure time. We identified a lipoprotein profile composed of four lipoprotein subfractions associated with TL (Pearson r = 0.347, p-value = 0.010), two lipoprotein subfractions associated with TERT expression (Pearson r = 0.316, p-value = 0.020), and five lipoprotein subfractions associated with WRAP53 expression (Pearson r = 0.379, p-value =0.005). After adjusting for known confounding factors, most lipoprotein profiles maintained the association with TL, TERT, and WRAP53. Overall, medium and small-sized HDL particles were associated with shorter telomeres and lower expression of TERT and WRAP53. Large HDL particles were associated with longer telomere and lower expression of WRAP53, but not with TERT. Our results suggest that the lipoprotein profiles are associated with telomere length, TERT, and WRAP53 expression and should be considered when assessing the risk of chronic diseases.

Regulating the Size of Simvastatin-loaded Discoidal Reconstituted Highdensity Lipoprotein: Preparation, Characterization, and Investigation of Cellular Cholesterol Efflux.

Reverse cholesterol transportation is essential for high-density lipoprotein (HDL) particles to reduce the cholesterol burden of peripheral cells. Studies have shown that particle size plays a crucial role in the cholesterol efflux capacity of HDLs, and the reconstituted HDLs (rHDLs) possess a similar function to natural ones. The study aimed to investigate the effect of particle size on the cholesterol efflux capacity of discoidal rHDLs and whether drug loadings may have an influence on this effect. Different-sized simvastatin-loaded discoidal rHDLs (ST-d-rHDLs) resembling nascent HDL were prepared by optimizing key factors related to the sodium cholate of film dispersion-sodium cholate dialysis method with a single controlling factor. Their physicochemical properties, such as particle size, zeta potential, and morphology in vitro, were characterized, and their capacity of cellular cholesterol efflux in foam cells was evaluated. We successfully constructed discoidal ST-d-rHDLs with different sizes (13.4 ± 1.4 nm, 36.6 ± 2.6 nm, and 68.6 ± 3.8 nm) with over 80% of encapsulation efficiency and sustained drug release. Among them, the small-sized ST-d-rHDL showed the strongest cholesterol efflux capacity and inhibitory effect on intracellular lipid deposition in foam cells. In addition, the results showed that the loaded drug did not compromise the cellular cholesterol efflux capacity of different-sized ST-d-rHDL. Compared to the larger-sized ST-d-rHDLs, the small-sized ST-d-rHDL possessed enhanced cellular cholesterol efflux capacity similar to drug-free one, and the effect of particle size on cholesterol efflux was not influenced by the drug loading.

THE PLASMA HDL-SUBFRACTION PROFILE IN HYPERTENSIVE PATIENTS WITH HIGH HDL-CHOLESTEROL LEVELS

Objective: The evaluation of cardiovascular risk (CVR) in arterial hypertension includes the estimation of high density lipoprotein (HDL-C). Although HDL-C is considered as a favorite CVR factor, the exact role that HDL-C subfraction profile play in the pathogenesis of atherosclerosis, especially in higher than usual HDL-C levels (>60 mg/dl) is currently under investigation. The aim of this study was to evaluate the plasma HDL subfraction profile of high HDL-C levels in hypertensive patients compared to normotensive subjects. Design and method: We studied 74 hypertensive patients (60 + 13 years, 62 females) and 24 normotensives, apparently healthy subjects (49 + 14 years, 22 females) with HDL-C equal or above 55 mg/dl. Cholesterol, HDL-C, and TG were determined enzymatically while LDL-C was calculated using the Friedewald formula. Plasma HDL particles were separated and determined electrophorically using Lipoprint System HDL Subfractions Kit. Aortic stiffness (c-f PWV) and central BP (cBP) were evaluated by carotid-femoral pulse wave velocity (Complior apparatus). Results: We found that hypertensive patients had increased age, BMI, office systolic and diastolic BP, PWV compared to normotensives. Regarding HDL, 10 HDL fractions were separated: fractions 1-3 were denoted as Large-HDL (L-HDL), fractions 4-7 constituted the Intermediate-HDL (I-HDL), and fractions 8-10 were denoted as Small-HDL (S-HDL) subfraction. Although HDL-C levels were similar between groups (76 + 13 vs. 81 + 17 mg/dl, p = 0.10), the percent distribution (%) of L-HDL was lower in hypertensives compared to normotensives (29.8±4.7% vs. 36.6±6.3%, p<0.001), % I-HDL was similar while % S-HDL was increased (27.3±3.7% vs. 20.4±4.4%, p<0.001). We found a significant negative correlation between L-HDL and SBP (rho = -0.48, p = 0.01) as well as cBP (rho = -0.52, p = 0.008) in younger hypertensive females before menopause (n = 26, 49 + 5 years). Conclusions: L-HDL particles, the most antiatherogenic HDL-C subfraction, were reduced in hypertensive patients with high HDL-C levels compared to normotensive subjects, suggesting that these patients are probably less protected against CV disease compared to normotensive subjects with similar HDL-C and LDL-C levels. Therefore, plasma HDL-subfraction profile might replace the HDL-C evaluation as a better biomarker of CVR in hypertensive patients, especially females before menopause.

HDL Function and Atherosclerosis: Reactive Dicarbonyls as Promising Targets of Therapy.

Epidemiologic studies detected an inverse relationship between HDL (high-density lipoprotein) cholesterol (HDL-C) levels and atherosclerotic cardiovascular disease (ASCVD), identifying HDL-C as a major risk factor for ASCVD and suggesting atheroprotective functions of HDL. However, the role of HDL-C as a mediator of risk for ASCVD has been called into question by the failure of HDL-C-raising drugs to reduce cardiovascular events in clinical trials. Progress in understanding the heterogeneous nature of HDL particles in terms of their protein, lipid, and small RNA composition has contributed to the realization that HDL-C levels do not necessarily reflect HDL function. The most examined atheroprotective function of HDL is reverse cholesterol transport, whereby HDL removes cholesterol from plaque macrophage foam cells and delivers it to the liver for processing and excretion into bile. Indeed, in several studies, HDL has shown inverse associations between HDL cholesterol efflux capacity and ASCVD in humans. Inflammation plays a key role in the pathogenesis of atherosclerosis and vulnerable plaque formation, and a fundamental function of HDL is suppression of inflammatory signaling in macrophages and other cells. Oxidation is also a critical process to ASCVD in promoting atherogenic oxidative modifications of LDL (low-density lipoprotein) and cellular inflammation. HDL and its proteins including apoAI (apolipoprotein AI) and PON1 (paraoxonase 1) prevent cellular oxidative stress and LDL modifications. Importantly, HDL in humans with ASCVD is oxidatively modified rendering HDL dysfunctional and proinflammatory. Modification of HDL with reactive carbonyl species, such as malondialdehyde and isolevuglandins, dramatically impairs the antiatherogenic functions of HDL. Importantly, treatment of murine models of atherosclerosis with scavengers of reactive dicarbonyls improves HDL function and reduces systemic inflammation, atherosclerosis development, and features of plaque instability. Here, we discuss the HDL antiatherogenic functions in relation to oxidative modifications and the potential of reactive dicarbonyl scavengers as a therapeutic approach for ASCVD.

An association of CSF apolipoprotein E glycosylation and amyloid-beta 42 in individuals who carry the APOE4 allele

Carrying the apolipoprotein E (ApoE) Ɛ4 allele is associated with an increased risk of cerebral amyloidosis and late-onset Alzheimer’s disease, but the degree to which apoE glycosylation affects its development is not clear. In a previous pilot study, we identified distinct total and secondary isoform-specific cerebral spinal fluid (CSF) apoE glycosylation profiles, with the E4 isoform having the lowest glycosylation percentage (E2 > E3 > E4). In this work, we extend the analysis to a larger cohort of individuals (n = 106), utilizing matched plasma and CSF samples with clinical measures of AD biomarkers. The results confirm the isoform-specific glycosylation of apoE in CSF, resulting from secondary CSF apoE glycosylation patterns. CSF apoE glycosylation percentages positively correlated with CSF Aβ42 levels (r = 0.53, p < 0.0001). These correlations were not observed for plasma apoE glycosylation. CSF total and secondary apoE glycosylation percentages also correlated with the concentration of CSF small high-density lipoprotein particles (s-HDL-P), which we have previously shown to be correlated with CSF Aβ42 levels and measures of cognitive function. Desialylation of apoE purified from CSF showed reduced Aβ42 degradation in microglia with E4 > E3 and increased binding affinity to heparin. These results indicate that apoE glycosylation has a new and important role in influencing brain Aβ metabolism and can be a potential target of treatment.

Total carotene plasma concentrations are inversely associated with atherosclerotic plaque burden: A post-hoc analysis of the DIABIMCAP cohort

Atherosclerosis is the major risk factor for cardiovascular disease (CVD), the first cause of death worldwide. Chronic low-grade inflammation and a sustained oxidative milieu are causatively related to atherosclerosis onset and progression, and therefore, dietary patterns rich in bioactive compounds with anti-inflammatory and antioxidant activities might likely contribute to revert or slowing the progression of atherosclerosis. The aim of this study is to analyse the association between fruit and vegetables intake, quantitatively measured through carotene plasma concentrations, and atherosclerotic burden, as a surrogate biomarker of CVD, in free-living subjects from the DIABIMCAP cohort study. The 204 participants of the DIABIMCAP Study cohort (Carotid Atherosclerosis in Newly Diagnosed Type 2 Diabetic Individuals, ClinicalTrials.gov Identifier: NCT01898572), were included in this cross-sectional study. Total, α-, and β-carotenes were quantified by HPLC-MS/MS. Lipoprotein analysis in serum was performed by 2D- 1H NMR- DOSY, and atherosclerosis and intima media thickness (IMT) were measured through standardized bilateral carotid artery ultrasound imaging. Subjects with atherosclerosis (n=134) had lower levels of large HDL particles than subjects without atherosclerosis. Positive associations were found between α-carotene and both large and medium HDL particles, and inverse associations were found between β- and total carotene, and VLDL and its medium/small particles. Subjects with atherosclerosis presented significantly lower plasma concentrations of total carotene compared with subjects without atherosclerosis. Plasma concentrations of carotene decreased as the number of atherosclerotic plaques increased, although after multivariate adjustment, the inverse association between β- and total carotene with plaque burden remained significant only in women. A diet rich in fruit and vegetables results in higher plasmatic carotene concentrations, which are associated with a lesser atherosclerotic plaque burden.

Total-, LDL-, and HDL-cholesterol, apolipoproteins, and triglycerides with risk of total and fatal prostate cancer in Black and White men in the ARIC study.

Cholesterol reduction is considered a mechanism through which cholesterol-lowering drugs including statins are associated with a reduced aggressive prostate cancer risk. While prior cohort studies found positive associations between total cholesterol and more advanced stage and grade in White men, whether associations for total cholesterol, low (LDL)- and high (HDL)-density lipoprotein cholesterol, apolipoprotein B (LDL particle) and A1 (HDL particle), and triglycerides are similar for fatal prostate cancer and in Black men, who experience a disproportionate burden of total and fatal prostate cancer, is unknown. We conducted a prospective study of 1553 Black and 5071 White cancer-free men attending visit 1 (1987-1989) of the Atherosclerosis Risk in Communities Study. A total of 885 incident prostate cancer cases were ascertained through 2015, and 128 prostate cancer deaths through 2018. We estimated multivariable-adjusted hazard ratios (HRs) of total and fatal prostate cancer per 1-standard deviation increments and for tertiles (T1-T3) of time-updated lipid biomarkers overall and in Black and White men. Greater total cholesterol concentration (HR per-1 SD = 1.25; 95% CI = 1.00-1.58) and LDL cholesterol (HR per-1 SD = 1.26; 95% CI = 0.99-1.60) were associated with higher fatal prostate cancer risk in White men only. Apolipoprotein B was nonlinearly associated with fatal prostate cancer overall (T2 vs. T1: HR = 1.66; 95% CI = 1.05-2.64) and in Black men (HR = 3.59; 95% CI = 1.53-8.40) but not White men (HR = 1.13; 95% CI = 0.65-1.97). Tests for interaction by race were not statistically significant. These findings may improve the understanding of lipid metabolism in prostate carcinogenesis by disease aggressiveness, and by race while emphasizing the importance of cholesterol control.

Dietary fat intakes, lipid profiles, adiposity, inflammation, and glucose in women and men in the Framingham Offspring Cohort.

Introduction: The role of dietary fat in the evolution of cardiometabolic disorders is highly controversial. As both dietary intake and the development of cardiometabolic risk differ by sex, we evaluated sex-specific differences in the associations between dietary fats (saturated and unsaturated) and four key cardiometabolic risk factors-lipid profiles, body fat, inflammation, and glucose regulation. Methods: We included 2391 women and men aged ≥30years in the prospective Framingham Offspring Cohort. Weight-adjusted dietary fats (saturated, monounsaturated, and polyunsaturated fats, including omega-3 and omega-6) were derived from 3-day dietary records. Analysis of covariance was used to derive adjusted mean levels of all outcomes. Results: In both men and women, intakes of saturated and monounsaturated fats were inversely associated with TG:HDL ratio (p < 0.02 for both types of fat). In women, higher omega-3 and omega-6 PUFAs were also inversely associated with TG:HDL (p < 0.05 for both), but for men, only omega-3 PUFAs were associated (p = 0.026). All types of dietary fat were beneficially associated with larger HDL particle sizes in both men and women, while only saturated and monounsaturated fats were associated with larger LDL particles in men. In addition, saturated and monounsaturated fats were associated with statistically significantly higher concentrations of HDL and lower concentrations of LDL and VLDL particles in both sexes, while polyunsaturated fat had favorable associations in women only. Saturated fat also had beneficial associations with three measures of body fat. For example, women with the highest (vs. lowest) saturated fat intake had a lower BMI (27.7 ± 0.25 vs. 26.2 ± 0.36kg/m2, p = 0.001); findings were similar in men (28.2 ± 0.25 vs. 27.1 ± 0.20, p = 0.002). Unsaturated fats had beneficial associations with body fat primarily in women. Finally, omega-3 PUFAs among women were inversely associated with interleukin-6 levels. There was no association between dietary fat intake and fasting glucose levels in either women or men. Discussion: In sum, we found no evidence of an adverse association between dietary fats and several surrogate markers of cardiometabolic health. This study suggests that different dietary fats may have divergent associations with cardiometabolic risk in women and men, perhaps owing to differences in food sources of the same dietary fats.

Abstract 227: Measuring HDL-apolipoprotein A-I Exchange By Subclass In Reconstituted And Human HDL

Objective: Levels of high density lipoprotein (HDL) are inversely associated with cardiovascular disease risk. HDL particles contain a diverse array of lipids, cholesterol, and proteins, and exist over a range of sizes ranging from about 8 nm to about 17 nm diameter, but it is not well understood how HDL size affects its function. In this study we examine the effect of HDL particle size on the rate of HDL-apolipoprotein A-I (apoA-I) exchange in reconstituted and human HDL particles. Method and Results: Reconstituted HDL particles were synthesized from 16:0-18:1n-9 PC, cholesterol, and recombinant apoA-I. Human HDL was isolated from plasma from healthy volunteers by density gradient ultracentrifugation. In both cases, the HDL was further separated by subclass using size exclusion chromatography. ApoA-I exchange was measured by incubating fluorescently-labeled, lipid-free apoA-I with HDL and quantifying the fluorescent signal appearing in the HDL region versus the lipid-free region of a nondenaturing gel over time. ApoA-I exchange rates increased inversely with particle size in both reconstituted and human HDL, with medium-sized HDL particles exhibiting twofold faster exchange rates compared to the largest HDL particles. Conclusions: Smaller HDL particles exhibit faster rates of HDL-apoA-I exchange in both reconstituted and human HDL particles. Reconstituted HDL particles provide an accurate approximation of apoA-I exchange in human HDL particles.

Abstract 406: Normalization Of Erythrocyte Morphology In Scarb1 -/- Mice By Bacterial Serum Opacity Factor Is Dependent On HDL-free Cholesterol

Compared to wild-type mice, HDL-receptor-deficient (Scarb1 -/- ) mice have higher plasma levels of free cholesterol (FC)-rich HDL and exhibit multiple pathologies—female infertility and deranged platelet and erythrocyte morphology and function. These pathologies are associated with a low mol% FC in ovaries, platelets, and erythrocytes, effects that are reversed by the HDL-lowering drug probucol. Some strains of Streptococcus pyogenes secrete a protein, serum opacity factor (SOF), which catalyzes the clouding i.e., opacification, of plasma. SOF specifically targets and quantitatively converts HDL into three products, that include a cholesteryl ester-rich microemulsion containing all the cholesterol content of &gt;100,000 HDL particles as well as APOE and its heterodimer with APOA2 as its sole apolipoproteins. Delivery of SOF with an adeno-associated virus (AAV SOF ) constitutively lowers plasma HDL-FC and reverses female infertility in Scarb1 -/- mice. Thus, we tested the hypothesis—AAV SOF delivery to Scarb1 -/- mice will normalize erythrocyte morphology in an HDL-FC dependent way. The erythrocyte morphology and FC content expressed as mol% FC of three groups of mice—WT, untreated Scarb1 -/- mice (control) and Scarb1 -/- mice receiving AAV SOF —were compared and correlated with their respective HDL-mol% FC. Among Scarb1 -/- mice, AAV SOF treatment normalized reticulocyte number, erythrocyte morphology and erythrocyte mol% FC. Plasma- and HDL-mol% FC positively correlated (p &lt; 0.0001) across all three groups of mice. HDL-mol% FC also positively correlated with erythrocyte mol% FC (p &lt; 0.0001). Finally, the erythrocyte mol% FC positively correlated with both the number of reticulocytes (p = 0.006) and abnormal erythrocytes (p &lt; 0.0001). Although less profound, AAV SOF treatment also reduced the FC contents of some extravascular tissues. HDL-FC spontaneously transfers from plasma lipoproteins to cell membranes in multiple tissues sites on a time scale of minutes to a few hours. FC-enrichment of erythrocytes, which are in contact with plasma HDL, was more profound than FC enrichment in tissues. AAV SOF treatment lowers both plasma HDL-FC and erythrocyte-FC and normalizes erythrocyte morphology and lipid composition in an HDL-FC dependent way.

High-Density Lipoprotein function is modulated by the SARS-CoV-2 spike protein in a lipid-type dependent manner

There is a close relationship between the SARS-CoV-2 virus and lipoproteins, in particular high-density lipoprotein (HDL). The severity of the coronavirus disease 2019 (COVID-19) is inversely correlated with HDL plasma levels. It is known that the SARS-CoV-2 spike (S) protein binds the HDL particle, probably depleting it of lipids and altering HDL function. Based on neutron reflectometry (NR) and the ability of HDL to efflux cholesterol from macrophages, we confirm these observations and further identify the preference of the S protein for specific lipids and the consequent effects on HDL function on lipid exchange ability. Moreover, the effect of the S protein on HDL function differs depending on the individuals lipid serum profile. Contrasting trends were observed for individuals presenting low triglycerides/high cholesterol serum levels (LTHC) compared to high triglycerides/high cholesterol (HTHC) or low triglycerides/low cholesterol serum levels (LTLC). Collectively, these results suggest that the S protein interacts with the HDL particle and, depending on the lipid profile of the infected individual, it impairs its function during COVID-19 infection, causing an imbalance in lipid metabolism.

Lipoprotein Particles as Shuttles for Hydrophilic Cargo

Lipoprotein particles (LPs) are excellent transporters and have been intensively studied in cardiovascular diseases, especially regarding parameters such as their class distribution and accumulation, site-specific delivery, cellular internalization, and escape from endo/lysosomal compartments. The aim of the present work is the hydrophilic cargo loading of LPs. As an exemplary proof-of-principle showcase, the glucose metabolism-regulating hormone, insulin, was successfully incorporated into high-density lipoprotein (HDL) particles. The incorporation was studied and verified to be successful using Atomic Force Microscopy (AFM) and Fluorescence Microscopy (FM). Single-molecule-sensitive FM together with confocal imaging visualized the membrane interaction of single, insulin-loaded HDL particles and the subsequent cellular translocation of glucose transporter type 4 (Glut4).

Estimated sdLDL-C for predicting high-risk coronary plaque features in psoriasis: a prospective observational study

BackgroundPsoriasis (PSO) is a skin disorder with systemic inflammation and high coronary artery disease risk. A distinct lipid phenotype occurs in psoriasis, which is characterized by high plasma triglycerides (TGs) with typically normal or even low LDL-C. The extent to which cholesterol on LDL subfractions, such as small dense LDL-C (sdLDL-C), are associated with vulnerable coronary plaque characteristics in PSO remains elusive.MethodsA recently developed equation for estimating sdLDL-C from the standard lipid panel was utilized in a PSO cohort (n = 200) with 4-year follow-up of 75 subjects. Coronary plaque burden was assessed by quantitative coronary computed tomography angiography (CCTA). Multivariate regression analyses were used for establishing associations and prognostic value of estimated sdLDL-C.ResultsEstimated sdLDL-C was positively associated with non-calcified burden (NCB) and fibro-fatty burden (FFB), which remained significant after multivariate adjustment for NCB (β = 0.37; P = 0.050) and LDL-C adjustment for FFB (β = 0.29; P < 0.0001). Of note, total LDL-C calculated by the Friedewald equation was not able to capture these associations in the study cohort. Moreover, in the regression modelling estimated sdLDL-C was significantly predicting necrotic burden progression over 4 years follow-up (P = 0.015), whereas LDL-C did not. Finally, small LDL particles (S-LDLP) and small HDL particles (S-HDLP), along with large and medium TG-rich lipoproteins (TRLPs) had the most significant positive correlation with estimated sdLDL-C.ConclusionsEstimated sdLDL-C has a stronger association than LDL-C with high-risk features of coronary atherosclerotic plaques in psoriasis patients.Clinical trial registrationURL: https://www.clinicaltrials.gov. Unique identifiers: NCT01778569

Low concentrations of medium-sized HDL particles predict incident CVD in chronic kidney disease patients

Patients with chronic kidney disease (CKD) are at high risk for CVD. However, traditional CVD risk factors cannot completely explain the increased risk. Altered HDL proteome is linked with incident CVD in CKD patients, but it is unclear whether other HDL metrics are associated with incident CVD in this population. In the current study, we analyzed samples from two independent prospective case-control cohorts of CKD patients, the Clinical Phenotyping and Resource Biobank Core (CPROBE) and the Chronic Renal Insufficiency Cohort (CRIC). We measured HDL particle sizes and concentrations (HDL-P) by calibrated ion mobility analysis and HDL cholesterol efflux capacity (CEC) by cAMP-stimulated J774 macrophages in 92 subjects from the CPROBE cohort (46 CVD and 46 controls) and in 91 subjects from the CRIC cohort (34 CVD and 57 controls). We tested associations of HDL metrics with incident CVD using logistic regression analysis. No significant associations were found for HDL-C or HDL-CEC in either cohort. Total HDL-P was only negatively associated with incident CVD in the CRIC cohort in unadjusted analysis. Among the six sized HDL subspecies, only medium-sized HDL-P was significantly and negatively associated with incident CVD in both cohorts after adjusting for clinical confounders and lipid risk factors with odds ratios (per 1-SD) of 0.45 (0.22–0.93, P = 0.032) and 0.42 (0.20–0.87, P = 0.019) for CPROBE and CRIC cohorts, respectively. Our observations indicate that medium-sized HDL-P—but not other-sized HDL-P or total HDL-P, HDL-C, or HDL-CEC—may be a prognostic cardiovascular risk marker in CKD.

Association between Nordic and Mediterranean diets with lipoprotein phenotype assessed by 1HNMR in children with familial hypercholesterolemia

Background and aimsBoth Nordic and Mediterranean diets are considered healthy despite notable regional differences. Although these dietary patterns may lower cardiovascular risk, it is unclear if they improve the lipoprotein phenotype in children with familial hypercholesterolemia (FH). The aim is to determine the impact of Nordic and Mediterranean diets on the advanced lipoprotein profile in children with heterozygous FH (HeFH). MethodsThis was a cross-sectional study performed in children with FH recruited from the Lipid Clinics at Sant Joan University Hospital in Reus (Spain) and Oslo University Hospital (Norway).Two-hundred fifty-six children (mean age 10 y/o; 48% girls): 85 Spanish and 29 Norwegian FH children, and 142 non-FH healthy controls (119 from Spain and 23 from Norway) were included in the study. A pathogenic FH-associated genetic variant was present in 81% of Spanish children with FH and all Norwegian children with FH. An 1H NMR based advanced lipoprotein test (Nightingale®) providing information on the particle number, size and lipid composition of 14 lipoprotein subclasses was performed and correlated to the dietary components. ResultsLevels of LDL-C, HDL-C and triglycerides were not significantly different between the Nordic and Mediterranean FH groups. Spanish children with FH had more LDL particles, mainly of the large and medium LDL subclasses, than Norwegian FH children. Spanish FH children also had more HDL particles, mainly medium and small, than Norwegian FH children. The mean LDL size of Spanish FH children was larger, while the HDL size was smaller than that of the Norwegian FH children. The HDL particle number and size were the main determinants of differences between the two groups. In Norwegian children with FH, dietary total fat and MUFAs showed a significant correlation with all apolipoprotein B-containing lipoproteins and LDL size, whereas there was no correlation to SFA. A weaker association pattern was observed in the Spanish children. ConclusionsThe lipoprotein profiles of Spanish and Norwegian children showed differences when studied by 1H NMR. These differences were in part associated with differences in dietary patterns.

HDL - Quo vadis

Many epidemiological studies found low plasma levels of high-density lipoprotein (HDL) cholesterol (HDL-C) associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). In cell culture and animal models, HDL particles show many anti-atherogenic actions. However, until now, clinical trials did not find any prevention of ASCVD events by drugs elevating HDL-C levels, at least not beyond statins. Also, genetic studies show no associations of HDL-C levels altering variants with cardiovascular risk. Therefore, the causal role and clinical benefit of HDL-C elevation in ASCVD are questioned. However, the interpretation of previous data has important limitations: First, the inverse relationship of HDL-C with the risk of ASCVD is limited to concentrations < 60 mg/dl (< 1.5 mmol/l). Higher concentrations do not reduce the risk of ASCVD events and are even associated with increased mortality. Therefore, neither the higher-the-better strategies of earlier drug developments nor the assumption of linear cause-and-effect relationships in Mendelian randomization trials are justified. Second, most of the drugs tested so far do not act specifically on HDL metabolism. Therefore, the futile endpoint studies question the clinical benefit of the investigated drugs, but not the importance of HDL in ASCVD. Third, the vascular functions of HDL are not exerted by its cholesterol content (i.e. HDL-C), but by a variety of other molecules. Comprehensive knowledge of the structure-function-disease relationships of HDL particles and their molecules is a prerequisite for testing their physiological and pathogenic relevance and possibly for optimizing the diagnosis and treatment of persons with HDL-associated risk of ASCVD, but also for other diseases, such as diabetes, chronic kidney disease, infections, autoimmune and neurodegenerative diseases.