HDL Particles Research Articles

The Emerging Potential of Apolipoprotein C-III Inhibition for ASCVD Prevention: A State-of-the-Art Review.

Multiple agents are being developed that inhibit apolipoprotein (apo) C-III. This state-of-the-art review examines their potential for atherosclerotic cardiovascular disease (ASCVD) risk reduction. Apo C-III, an apolipoprotein on the surface of triglyceride-rich lipoproteins (TRLs), impairs clearance of TRLs through both lipoprotein lipase dependent and independent pathways, thereby resulting in increased concentrations of triglycerides. Apo C-III has also been shown to have pro-atherogenic effects when bound to high-density lipoprotein (HDL) particles. Classical and genetic epidemiology studies provide support for the concept that apo C-III is associated with an increased risk of ASCVD events. Drug efficacy of agents that silence APOC3 mRNA has been studied in populations with varying hypertriglyceridemia severity, including those with familial chylomicronemia syndrome, multifactorial chylomicronemia syndrome/severe hypertriglyceridemia, and mixed hyperlipidemia. Randomized controlled trials have reported significant reductions in TG and non-HDL cholesterol levels among these patients treated with APOC3 inhibitors. Upcoming clinical outcomes trials seek to establish a role for APOC3 inhibitors to reduce risk of ASCVD.

Abstract 4120854: Case Report: Elevated HDL in Familial Hyper-Alpha-Lipoproteinemia: Atheroprotective or Atherogenic?

Introduction: Familial hyper-alpha-lipoproteinemia (HALP) is a heterogenous genetic lipid disorder that is found in only 8% of the population and manifests as elevated HDL levels above the 90 th percentile. HALP is due to mutations in various genes including cholesteryl ester transfer protein (CETP), hepatic lipase, or apolipoprotein C-III (APOC3). While epidemiological studies have noted an inverse relationship between high HDL and the development of coronary artery disease, recent data have shown a lack of causal atheroprotective effects. We present a case of a patient with significantly elevated HDL and peripheral vascular disease. Case Description: Patient is a 64-year-old female with past medical history of peripheral artery disease with occlusion of the left femoral artery and popliteal arteries status post angioplasty, hypertension, type 2 diabetes, alcohol use, and CKD Stage 4 who presented to the advanced lipid clinic for management of elevated lipoproteins. Patient’s laboratory data was significant for total cholesterol (TC) of 375 mg/dL, a high-density lipoprotein (HDL) of >200 mg/dL, triglycerides (TG) of 66 mg/dL, and a low-density lipoprotein (LDL) of 175 mg/dL. Further testing revealed elevated apolipoprotein A-I of 231 mg/dL. Patient was subsequently initiated on a high intensity statin with improvement in her lipid panel with a TC of 247 mg/dL, HDL of 133 mg/dL, TG of 50 mg/dL, and LDL of 106 mg/dL, with plan for further uptitration of lipid therapy to target LDL <70 mg/dL. Discussion: CETP exchanges cholesteryl esters from HDL for TG, making HDL smaller and more TG-rich. Studies have shown that in vitro addition of CETP and hepatic lipase, which hydrolyzes phospholipids and TG, into CETP-deficient patients led to the development of very small HDL particles that were able to remove cholesterol from lipid laden macrophages. Conversely, larger HDL molecules seen in CETP-deficient patients did not have such anti-atherogenic properties. In addition to recognizing HALP in the setting of elevated HDL, it is also important to exclude secondary causes of elevated HDL, such as primary biliary cirrhosis and high-dose niacin. Genetic testing should also be considered.

Differential proteomic profiles of exosomes in pediatric and adult adamantinomatous craniopharyngioma cyst fluid.

Adamantinomatous craniopharyngiomas (ACPs), commonly seen in pediatrics and adults often present with large cystic cavities that can compress surrounding tissues, causing severe visual and endocrine symptoms. Complete resection of cystic ACP is challenging, frequently leading to postoperative recurrence. The composition of the cystic fluid is complex, and to date, there has been limited research focusing on exosomes within ACP cyst fluid. We collected cyst fluid from 12 ACP patients and confirmed the presence of exosomes. Subsequently, we conducted exosomal proteomic analysis using LC-MS/MS. The patients were divided into pediatric and adult groups for the analysis of differential protein enrichment, followed by comprehensive bioinformatics analysis, including GO analysis, KEGG analysis, and PPI network analysis, among other functional pathway and protein interaction analyses. Immunohistochemistry was used to determine the tissue expression distribution of the differential protein APOA1. In our data analysis, 64 significantly differentially expressed proteins were identified, with 37 being overexpressed in the pediatric group and 27 in the adult group. Our results revealed that exosomal proteins in the pediatric group were predominantly enriched in modules and pathways related to high-density lipoprotein particle, apolipoprotein receptor binding, and the PPAR signaling pathway. Additionally, APOA1, as the hub protein with the highest connectivity in the differential protein interaction network, may play a critical role in β-amyloid metabolism pathways in pediatric ACP. This study is the first to construct a proteomic map of ACP cyst fluid exosomes, suggesting significant differences in the tumor microenvironment's lipid metabolism between pediatrics and adults.

Serum Metabolome Signature Response to Different Types of Resistance Training.

Pneumatic resistance training (PRT) facilitates a longer time under tension that might lead to greater changes in body composition when compared to traditional resistance training (TRT), possibly enhancing serum metabolite concentrations indicative of healthy metabolic function. To assess the impact of PRT and TRT on muscular strength, body composition, and serum metabolome, 69 men (age: 31.8±7.2 years, height: 179.7±5.4 cm, weight: 81.1±9.9 kg) were randomized into two 10-week intervention groups (PRT:n=24 and TRT:n=24) and one control group (CON:n=21). Serum metabolite concentrations were assessed before and after the training intervention by high-throughput nuclear magnetic resonance. Fat mass and lean mass were obtained by bioimpedance analysis. The training intervention resulted in an increase in lean mass for both PRT (1.85±2.69%; p=0.003) and TRT (2.72±4.53%; p=0.004), while only PRT reduced statistically significantly in body fat percentage (PRT: -5.08±10.76%; p=0.019). Only in PRT and TRT significant increases in small high-density lipoproteins (S-HDL-L) and small HDL particles (S-HDL-P) were observed. When controlling for fat and lean mass, the effects on S-HDL-L/S-HDL-P diminished. Network analysis may suggest that PRT and TRT result in an increase in network connectivity and robustness. It appears that the observed improvements are associated with changes in body composition.

Plasma proteomic signature of chronic psychosocial stress in mice

Chronic stress significantly impacts both physical and mental wellbeing, increasing risk of cardiovascular disease, immune dysregulation, and psychiatric conditions such as depression and anxiety disorders. The plasma proteome is a valuable source of biomarkers of health and disease, but the limited number of studies exploring the potential of the plasma proteome as a biomarker for stress-related disorders underscores the importance of further investigation of the effects of chronic stress on the plasma proteome. The aim of this study was to examine the effect of a 5-week chronic psychosocial stress paradigm on the plasma proteome in mice and to determine if any affected proteins correlated with stress-induced changes in behaviour and physiology, and thus might represent biomarkers of negative impacts of chronic stress. Using LC-MS/MS proteomic analysis, 38 proteins in the mouse plasma proteome were identified to be affected by chronic psychosocial stress. Functional analysis revealed that these proteins clustered into biological functions including inflammatory response, regulation of the immune response, complement and coagulation cascades, lipid metabolic process, and high-density lipoprotein particles Correlation analyses of the identified proteins with stress-induced behavioural or physiological changes stress revealed significant correlations between stress-induced anxiety-like behaviour and Phosphatidylinositol-glycan-specific phospholipase D, Complement C2, Epidermal growth factor receptor, Prosaposin, Actin-related protein 2/3 complex subunit 1B, Maltase-glucoamylase, Mannosyl-oligosaccharide 1,2-alpha-mannosidase IA and Fibrinogen-like protein 1. Chronic psychosocial stress blunted acute stress-induced corticosterone release, and this correlated with abundance of Pyrethroid hydrolase Ces2a; N-fatty-acyl-amino acid synthase/hydrolase Pm20d1, Mannosyl-oligosaccharide 1,2-alpha-mannosidase IA, Alpha-2-macroglobulin-P and L-selectin. Finally, stress-induced reductions in both brown and epididymal fat correlated with Phosphatidylinositol-glycan-specific phospholipase D, Complement C2, Epidermal growth factor receptor, Kininogen-1, Apolipoprotein M, Angiopoietin-related protein 3, Proprotein convertase subtilisin/kexin type 9, and Lipopolysaccharide-binding protein. These findings demonstrate that chronic psychosocial stress induces alterations in plasma proteins implicated in key biological processes and pathways related to stress response, immune function, and lipid metabolic regulation. Further investigation into these proteins may provide new avenues for identification of biomarkers or mediators of stress-induced pathology.

Relation of apolipoprotein C3 to risk of major adverse cardiovascular events and death after acute coronary syndrome on a background of optimized statin treatment

Abstract Background Apolipoprotein C3 (ApoC3), a component of triglyceride-rich lipoproteins and some low-density lipoprotein and high-density lipoprotein particles, has been shown to predict incident coronary heart disease (CHD) and major adverse cardiovascular events (MACE). However, it is unknown whether ApoC3 predicts risk in patients with acute coronary syndrome (ACS) receiving contemporary therapies including optimized statin treatment, and if any such association is independent of apolipoprotein B (ApoB) levels. Purpose We assessed the association of ApoC3 with first MACE (CHD death, nonfatal myocardial infarction, fatal or nonfatal ischaemic stroke, or hospitalization for unstable angina) and all-cause death in patients with recent ACS treated with high-intensity or maximum-tolerated statin and blinded PCSK9 inhibitor (alirocumab, ALI) or placebo (PBO). Methods ApoC3 was measured by mass spectrometry at baseline (n=11,956) and after 4 months (M4; n=11,176) of treatment with ALI or PBO in the ODYSSEY OUTCOMES trial (which had 18,924 total participants). In continuous and spline analyses adjusted for treatment group and ApoB, we assessed the association of baseline ApoC3 with risk of MACE and death. In the ALI group we determined association of change in ApoC3 from baseline to M4 with risk of MACE and death after M4 in a model adjusted for baseline ApoC3 and ApoB, and the change in ApoB from baseline to M4. Results Median (Q1, Q3) baseline ApoC3 concentration was in a normal range [85 (65, 113) mg/L]. Continuous ApoC3 was not related to MACE (p=0.50) or death (p=0.51); spline analysis showed a slight curvilinear association of baseline ApoC3 with risk of MACE and death, but no clinically meaningful relationship (Figure). Findings were similar in the PBO group alone, and without adjustment for ApoB (data not shown). At M4, the median (Q1, Q3) change from baseline in ApoC3 was -10 (-27, -5; p<0.0001) mg/L with ALI and 2 (-14, 18; P = NS) mg/L with PBO. Overall, ALI significantly reduced the incidence of MACE (10.1% vs 12.1%; p=0.0006) and death (3.5% vs 4.2%; p=0.045) compared with PBO among those with available baseline ApoC3. However, the change in ApoC3 on treatment with ALI did not predict the risk of MACE or death after M4. Findings were qualitatively similar without adjustment for ApoB or its change. Conclusion In a cohort with recent ACS receiving optimized statin therapy and with median baseline ApoC3 in a normal range, ApoC3 did not provide clinically meaningful prediction of cardiovascular events or death. A modest reduction of ApoC3 by ALI did not associate with subsequent risk of MACE or death. It remains uncertain whether targeted therapies producing larger reductions in ApoC3 from higher baseline levels will affect cardiovascular risk.

Electronegative ApoCIII-Rich HDL promotes cellular damage and vascular aging

Abstract Background Experimental studies attributing HDL a cardioprotective effect are challenged by well-designed randomized controlled trials showing largely neutral results, which might be related to more recent observations that certain HDL particles exert detrimental effects. This study explores the effects of electronegative HDL on cellular damage and vascular aging. Using anion-exchange chromatography, HDL was divided into five subclasses (H1 to H5) based on increasing electronegativity. Compared to the health-promoting H1, the most electronegative subclass, H5 contains significantly higher levels of ApoCIII and triglycerides (TG). Purpose Herein, we aim to explore the cellular and molecular mechanisms underpinning H5-induced pathology in human umbilical vein vascular endothelial cells (HUVECs), which may accelerate vascular aging preceding the development of atherosclerotic cardiovascular disease (ASCVD). Methods H1 and H5 were isolated from patients with metabolic syndrome (MetS). To gauge the impact of H5 on vascular integrity, HUVECs were treated with solvent, H1, or H5 at concentrations of 25, 50, or 100 µg/mL. Cell viability and apoptosis were evaluated using the MTT assay and PI/Calcein fluorescent staining, respectively. Immunofluorescence staining and immunoblotting, focusing on 8-oxodG, P53, and β-gal, proxies of DNA damage and cellular senescence, were performed. Senescence-associated secretory phenotype (SASP) analysis was done to elucidate the senescent mechanism. By harnessing Mitosox imaging reactive oxygen species (ROS) synthesis was monitored. Finally, unbiased lipid- and transcriptomics were used to identify lipid components potentially involved in H5 signaling. Results As compared to controls, MetS patients exhibited more electronegative HDL particles, as indicated by increased H5 (1.604±0.410% vs 4.598±4.712%, P=0.0016). Remarkable elevations were noted in individuals with severe clinical complications, as shown in the representative patient with left ventricular hypertrophy, chronic coronary syndrome, and heart failure (Fig. 1). In HUVECs, H5 but not H1 reduced cell viability and increased apoptosis in a concentration-dependent manner. In parallel, H5 but not H1 induced cell aging, ROS production, and DNA damage, with SASP cytokines including IL-1β, IL-6, CCL2, TNF-α, and γH2AX (Fig. 1). Notably, compared to H1, H5 exhibited high contents of various TG species, impairing H5’s anti-inflammatory and antioxidant capacities, along with reductions in several phosphatidylcholines that may constitute essential cell membrane structural components, as evidenced by lipidomic studies (Fig. 2). Conclusion H5, the most electronegative and dysfunctional HDL subfraction, is capable of inducing DNA damage, oxidative stress, and senescence in vascular ECs. Its notable elevation in patients with MetS highlights a previously unrecognized etiology, shedding light on how electronegative HDL may contribute to and expedite ASCVD.Fig 1Fig 2

Triple-hormone receptor agonist retatrutide significantly improves lipoprotein and apolipoprotein profiles in participants with obesity or overweight

Abstract Background In a phase 2 study in participants who have obesity or overweight but not type 2 diabetes (T2D) (n=338), retatrutide (RETA), an agonist of GIP, GLP-1 and glucagon receptors, reduced body weight, glycated hemoglobin, triglycerides (TG), LDL-C and VLDL-C. Purpose To better understand the effects of RETA on the serum lipid profile we analyzed changes in apolipoprotein levels and distribution and size of lipoprotein particles. Methods Adult participants with obesity (BMI ≥30 kg/m2), or overweight (BMI ≥ 27 kg/m2 and < 30 kg/m2) with a weight-related comorbidity, and without T2D were randomized to receive RETA 1, 4, 8, 12 mg or placebo for 48 weeks. Lipids panel (including calculated non-HDL-C), apolipoproteins (apo) and NMR lipoprotein profiles were measured at baseline, 24 and 48 weeks in fasting plasma samples. Data were analyzed using a mixed model for repeated measures after log transformation. Results RETA dose-dependently reduced non-HDL-C up to 22.2% and 26.9% and apoB up to 19.6% and 24.2% at 24 and 48 weeks, respectively (Figure). At 48 weeks, RETA reduced TG and apoC-III levels up to 40.6% and 38.0%, respectively. RETA greatly reduced the total number of TG-rich lipoprotein particles (TRLP) and all subfractions of TRLP (large, medium and small) at 48 weeks (Table). Since the reduction in large and medium TRLP was greater than the reduction in small TRLP, the average size of TRLP was smaller following treatment with RETA. RETA reduced the number of total and highly atherogenic small LDL particles (LDLP), while total and small HDL particles (HDLP) were only slightly reduced. The average size of HDLP increased following treatment with RETA. At 48 weeks, the NMR-derived lipoprotein insulin resistance score was dose-dependently decreased by 27.4%, 31.7% and 32.5% with 4 mg, 8 mg and 12 mg, respectively, following RETA treatment. Conclusions RETA treatment for 48 weeks dose-dependently reduced levels of non-HDL-C and apoB and the number of total and small LDL particles, suggesting an improvement in atherogenic lipoprotein profile and cardiovascular risk in subjects who have obesity or overweight but not T2D.

Association between lipoprotein particle concentration and size and progression of coronary plaque: the MACS Longitudinal Coronary CT angiography study

Abstract Background People living with HIV have greater risk of cardiovascular diseases (CVD) than people without HIV and tend to have different risk profiles, including higher serum triglycerides and lower LDL cholesterol levels. Nuclear magnetic resonance (NMR) provides a detailed phenotype of lipoproteins. Purpose To examine the associations between lipoprotein particle concentrations and size and progression of coronary artery plaque among people living with and without HIV, and whether these associations differ by HIV serostatus. Methods Men with no clinical CVD in the Multicenter AIDS Cohort Study (MACS) who underwent a coronary CT angiography at baseline (2010-13) and follow-up (2015-17) were included. NMR spectroscopy was completed on fasting serum samples at baseline. Logistic regression models for the change in total coronary plaque volume (in tertiles) were estimated with NMR-derived lipoproteins as predictors. Levels were log-transformed and standardized to make results comparable. Models were adjusted for demographics, statin use and HIV serostatus (model 1) with addition of CVD risk factors (model 2). Interactions by HIV serostatus were also tested. Results A total of 549 men (314 with HIV; 235 without HIV) were included. Mean age was 53 ±7 years; 58% were White, 30% Black, and 12% Hispanic. Coronary plaque was present in 70% and plaque volume progressed in 79% of the cohort. Among men with HIV, 81% had undetectable HIV RNA and 12% had a diagnosis of AIDS at baseline. Men with HIV had significantly higher levels of small LDL-P, and total, medium and large VLDL-P levels compared to men without HIV, and lower levels of total, small and large HDL-P (Table 1). Men with HIV had significantly greater progression of plaque volume (37 mm3) compared to men without HIV (31 mm3, p<0.05). Levels of total and small LDL-P concentrations were directly associated with plaque progression, whereas large HDL-P was inversely associated with plaque progression in the combined sample (Model 2). Associations between total and small LDL-P with plaque progression were stronger in men with HIV than in men without HIV in models 1 and 2 (interaction p<0.01). While associations in fully adjusted models for total VLDL-P and small VLDL-P were significant in men without HIV, there were no significant associations between these particle concentrations with coronary plaque progression among men without HIV (interaction p< 0.01) (Model 2, Table 2). Conclusion Associations between lipid particle concentrations and coronary plaque progression differed between men with and without HIV, with stronger associations seen in men without HIV for total and small LDL-P. Despite having higher VLDL and lower HDL particle concentrations at baseline, these particle concentrations were only associated with plaque progression in men without HIV. Further research is needed to elucidate HIV specific factors for plaque progression to tailor risk reduction strategies.

Associations Between High-Density Lipoprotein Cholesterol Efflux and Brain Grey Matter Volume.

Objective: High-density lipoprotein cholesterol efflux function may prevent brain amyloid beta deposition and neurodegeneration. However, the relevance of this finding has not been established in the diverse middle-aged population. Methods: We examined 1826 adults (47% Black adults) who participated in the Dallas Heart Study to determine associations between high-density lipoprotein (HDL) measures and brain structure and function. White matter hyperintensities (WMH) and whole-brain grey matter volume (GMV) were measured using brain MRI, and the Montreal Cognitive Assessment (MoCA) was used to measure neurocognitive function. HDL cholesterol efflux capacity (HDL-CEC) was assessed using fluorescence-labeled cholesterol efflux from J774 macrophages, and HDL particle size measures were assessed using nuclear magnetic resonance (NMR) spectroscopy (LipoScience). Multivariable linear regressions were performed to elucidate associations between HDL-CEC and brain and cognitive phenotypes after adjustment for traditional risk factors such as age, smoking status, time spent in daily physical activity, and education level. Results: Higher HDL-CEC and small HDL particle (HDL-P) concentration were positively associated with higher GMV normalized to total cranial volume (TCV) (GMV/TCV) after adjustment for relevant risk factors (β = 0.078 [95% CI: 0.029, 0.126], p = 0.002, and β = 0.063 [95% CI: 0.014, 0.111], p = 0.012, respectively). Conversely, there were no associations between HDL measures and WMH or MoCA (all p > 0.05). Associations of HDL-CEC and small HDL-P with GMV/TCV were not modified by ApoE-ε4 status or race/ethnicity. Interpretation: Higher HDL cholesterol efflux and higher plasma concentration of small HDL-P were associated with higher GMV/TCV. Additional studies are needed to explore the potential neuroprotective functions of HDL.

Distinct roles of size-defined HDL subpopulations in cardiovascular disease.

Doubts about whether high-density lipoprotein-cholesterol (HDL-C) levels are causally related to atherosclerotic cardiovascular disease (CVD) risk have stimulated research on identifying HDL-related metrics that might better reflect its cardioprotective functions. HDL is made up of different types of particles that vary in size, protein and lipid composition, and function. This review focuses on recent findings on the specific roles of HDL subpopulations defined by size in CVD. Small HDL particles are more effective than larger particles at promoting cellular cholesterol efflux because apolipoprotein A-I on their surface better engages ABCA1 (ATP binding cassette subfamily A member 1). In contrast, large HDL particles bind more effectively to scavenger receptor class B type 1 on endothelial cells, which helps prevent LDL from moving into the artery wall. The specific role of medium-sized HDL particles, the most abundant subpopulation, is still unclear. HDL is made up of subpopulations of different sizes of particles, with selective functional roles for small and large HDLs. The function of HDL may depend more on the size and composition of its subpopulations than on HDL-C levels. Further research is required to understand how these different HDL subpopulations influence the development of CVD.

Advanced lipid testing in children: a call for pediatric reference intervals

Abstract Introduction Abnormal serum lipid levels in childhood are associated with dyslipidemia and increased risk of cardiovascular disease in adulthood. High prevalence of childhood obesity in the US has increased concerns about the adverse effects of abnormal lipids in children, prompting recommendations for universal lipid screening in adolescents. While specialized analysis of lipoproteins by nuclear magnetic resonance (NMR) has been predominately used in adults with risk factors for CVD, our laboratory also receives pediatric samples for NMR testing, most commonly associated with diagnostic codes for hyperlipidemia and/or abnormal weight gain. Currently adult-based reference ranges for the NMR lipoprotein measurements are used in children. The objective of this pilot study was to compare lipoprotein profiles of healthy adults and children and to assess the impact of reference intervals for children on clinical interpretation of pediatric results. Methods Serum samples were collected from 60 healthy children, ages 1 – 17 years, and 148 healthy adults, ages 19 – 64 years old. NMR lipoprotein analysis was performed using the Axinon lipoFIT by NMR assay on a 600 MHz NMR (Bruker). Statistical analysis was conducted in Excel and GraphPad Prism. Reference intervals (RIs) were determined in EP Evaluator as the central 95% interval. Results The levels of atherogenic low-density lipoprotein particle number (LDL-P) and small LDL-P (sLDL-P) were significantly lower in children compared to adults: 783±222 vs 1212±412 nmol/L and 302±142 vs 498±306 nmol/L, respectively (p<0.00001). Additionally, LDL size (LDL-s) was significantly larger in children than adults (21.23±0.29 vs 21.06±0.44 nm, p=0.006), reflecting prevalence of less dense LDL-P in the former group. Pediatric samples also had lower number of anti-atherogenic high-density lipoprotein particles (HDL-P) compared to adults: 29.4±4.6 vs 33.5±4.6 µmol/L, p<0.00001. The significant differences in the number and size of lipoprotein particles between adults and children implies that currently used adult reference intervals might not be appropriate for evaluating pediatric NMR samples. Therefore, we estimated RIs for our heathy pediatric and adult cohorts and applied these RIs to our retrospective data of 618 samples from children 1-17 years old, which were submitted for NMR lipoprotein testing in recent years. The analysis showed that using the adult RIs, 37% and 27% of pediatric samples would not flag for abnormally elevated LDL-P and sLDL-P, respectively; but they would be flagged based on the RI derived from our pediatric cohort. Moreover, 12% pediatric samples flagged for low HDL-P would have normal HDL-P levels if pediatric RIs are used instead of adult RIs. Conclusions Use of adult reference intervals in children may result in misclassification of lipid status and underestimation or overestimation of dyslipidemia and CVD risk in children. This pilot study highlights the need for pediatric reference intervals to guide interpretation of advanced lipid testing in children.

NMR Insights into Lipoprotein Particles: analyzing correlations with traditional lipid measurements

Abstract Introduction Lipid metabolism plays a crucial role in various physiological processes. Lipid molecules are transported by lipoproteins, and the intricate involvement of lipoproteins in cardiovascular disease (CVD) is well-established, given their diverse size, density, and lipid composition. The emergence of Nuclear Magnetic Resonance (NMR) spectroscopy, a high-resolution analytical technique, promotes the assessment of lipoprotein particle numbers and sizes. Studies suggest that the measurement of total low-density lipoprotein particle numbers (LDL-P), small LDL-P (SLDL-P), and total high-density lipoprotein particle numbers (HDL-P) provides better evaluation of risk of CVD than enzymatic-based measurements of LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C). Our study examined the correlation between NMR-derived lipoprotein profiles and traditional cholesterol measurements in control and patient populations. Methods Fasting serum samples were collected from healthy male and female donors (n=148), ages 21-64 years. The analysis also included the results from >20,000 patients’ samples submitted to our laboratory for NMR lipid testing. We assessed LDL-P, SLDL-P, HDL-P, large HDL (LHDL-P), and HDL size (HDL-S) by NMR. In addition, total cholesterol (TC) and HDL-C were measured using traditional automated enzymatic assays (Roche Diagnostics); LDL-C was calculated. Statistical analyses, including Spearman correlation, were performed using GraphPad Prism software. Spearman coefficient (r) ≥0.75 indicated a strong correlation, r <0.5 indicated a weak correlation. Results HDL-C only moderately correlated with total HDL-P in samples collected from controls (rcontrols=0.52) and patients (rpatients=0.68), while showing better correlation with LHDL-P (rcontrols=0.90, rpatients=0.89). Traditional LDL-C strongly correlated with total LDL-P (rcontrols=0.76, rpatients=0.81), but showed only weak correlation with SLDL-P (rcontrols=0.42, rpatients=0.28), which is considered more atherogenic and predictive of CVD risk than LDL-C or total LDL-P. Interestingly, among various lipoprotein parameters, SLDL-P correlated the strongest with HDL-S in both study populations (rcontrols=-0.87, rpatients=-0.84). Samples with higher number of SLDL-P also had smaller size of HDL-P, although the number of total HDL-P did not differ between high vs low SLDL-P samples. In contrast, only moderate negative correlation was observed between SLDL-P and traditional HDL-C (rcontrols=-0.74, rpatients=-0.68), suggesting that the size of HDL particles might add value in evaluating CVD risk. Conclusion The NMR technology has advantage over traditional measurements in stratifying an individual’s lipoprotein milieu. It provides insights into the number of small LDL particles and size of HDL particles, which are not included in standard lipid testing and may allow for more individualized patient care. Incorporation of lipoprotein size and particle number in clinical guidelines may help physicians with assessment CVD risk and treatment monitoring.

The Composition of the HDL Particle and Its Capacity to Remove Cellular Cholesterol Are Associated with a Reduced Risk of Developing Active Inflammatory Rheumatoid Arthritis.

In rheumatoid arthritis (RA), the risk of cardiovascular death is 50% higher compared to the general population. This increased risk is partly due to the systemic inflammation characteristic of RA and changes in the lipoprotein profiles. This study investigated plasma lipid levels, lipid ratios, and the composition and functionality of high-density lipoprotein (HDL) in control individuals and RA subjects based on the disease's inflammatory score (DAS28). This study included 50 control (CTR) individuals and 56 subjects with RA, divided into remission/low-activity disease (DAS28 < 3.2; n = 13) and active disease (DAS28 ≥ 3.2; n = 43). Plasma lipids (total cholesterol, TC; triglycerides, TG) and the HDL composition (TC; TG; phospholipids, PL) were determined using enzymatic methods; apolipoprotein B (apoB) and apoA-1 were measured by immunoturbidimetry. HDL-mediated cholesterol efflux and anti-inflammatory activity were assessed in bone marrow-derived macrophages. Comparisons were made using the Mann-Whitney test, and binary logistic regression was used to identify the predictors of active RA. A p-value < 0.05 was considered significant. TC, HDLc, and the TC/apoB ratio were higher in RA subjects compared to the CTR group. Subjects with active disease exhibited higher levels of TG and the TG/HDLc ratio and lower levels of HDLc, the TG/apoB ratio, TC, and apoA-1 in HDL particles compared to those with remission/low-activity RA. Increased levels of HDLc [odds ratio (OR) 0.931, 95% CI = 0.882-0.984], TC/apoB (OR 0.314, 95% CI = 0.126-0.78), HDL content in TC (OR 0.912, 95% CI = 0.853-0.976), PL (OR 0.973, 95% CI = 0.947-1.000), and apoA-1 (OR 0.932, 95% CI = 0.882-0.985) were associated with a decreased risk of active disease, but BMI (OR 1.169, 95% CI = 1.004-1.360) and TG (OR 1.031, 95% CI = 1.005-1.057) were positively associated with active disease. A reduction in HDL-mediated cholesterol efflux increased the OR for active RA by 26.2%. The plasma levels of HDLc, along with the composition and functionality of HDL, influence the inflammatory score in RA and may affect the development of cardiovascular disease.

Efficacy of Food Industry By-Product β-Glucan/Chitin–Chitosan on Lipid Profile of Overweight and Obese Individuals: Sustainability and Nutraceuticals

Fat-binding nutraceutical supplements have gained considerable attention as potential cholesterol-lowering strategies to address dyslipidemia in overweight and obese individuals. This study aimed to evaluate the effects of a polysaccharide-rich compound containing β-glucan/chitin–chitosan (βGluCnCs) on lipid profiles and lipoprotein function. In a prospective, two-arm clinical trial, 58 overweight and obese individuals were randomized to receive either 3 g/day of βGluCnCs or a placebo (microcrystalline cellulose) for 12 weeks. Serum lipids and lipoprotein functions were assessed at baseline and at 4-week intervals throughout the study. The administration of βGluCnCs led to a significant increase in HDL cholesterol (HDLc) levels and improved HDLc/non-HDLc and HDLc/total cholesterol (TC) ratios, while reducing apolipoprotein B (ApoB) levels (p &lt; 0.05). However, the intervention did not affect HDL particle diameter, particle number, or lipoprotein functionality. Women demonstrated greater sensitivity to changes in HDLc during βGluCnCs supplementation, whereas men exhibited a significant reduction in ApoB levels. When stratified by baseline LDL cholesterol (LDLc) levels (cut-off: 130 mg/dL), the increase in HDLc and the ApoA1/ApoB ratio was found in the low-LDL group. In contrast, the high-LDL group experienced a significant reduction in atherogenic non-LDLc and LDLc, along with an improvement in HDL’s antioxidant capacity after βGluCnCs intervention. These changes were not statistically significant in the placebo group. In conclusion, our study demonstrated that daily supplementation with βGluCnCs significantly improved lipid profiles, with effects that varied based on sex and baseline LDLc levels.

Relationship of high-density lipoprotein subfractions and apolipoprotein A-I with fat in the pancreas.

To investigate the associations of high-density lipoprotein (HDL) subfractions and apolipoprotein A-I (apo A-I) with fat in the pancreas. A total of 170 individuals were studied. All participants underwent magnetic resonance imaging on a single 3.0-Tesla scanner to determine the presence/absence of fatty pancreas. HDL subfractions were measured using a commercially available lipoprotein subfractions testing system and classed as large, intermediate and small HDL. Both unadjusted and adjusted (accounting for demographics, anthropometrics, insulin resistance and other covariates) logistic regression models were built. Individuals with fatty pancreas had significantly lower circulating levels of the large HDL class and apo A-I. Every unit decrease in the large HDL class was associated with a 93% increase in the likelihood of fatty pancreas in the most adjusted model (P < .001). Every unit decrease in apo A-I was associated with a 45% increase in the likelihood of fatty pancreas in the most adjusted model (P = .012). The intermediate and small HDL classes were not significantly associated with fatty pancreas. Fat in the pancreas is inversely associated with the circulating levels of large HDL particles and apo A-I. Purposely designed studies are warranted to investigate the potential of fatty pancreas as an indicator of the risk of cardiovascular diseases.

High-density lipoprotein functionality in cholesterol efflux in early childhood is related to the content ratio of triglyceride to cholesterol

Cholesterol efflux capacity (CEC), commonly measured as a useful risk marker of atherosclerotic cardiovascular disease, depends on high-density lipoprotein (HDL) functionality and its concentration. We defined the relative HDL functionality in cholesterol efflux, not influenced by HDL concentration, as the ratio of measured CEC to standardized CEC (stCEC) based on HDL-cholesterol (HDL-C) of each individual using the curve regression equation obtained from the correlation. HDL-C, CEC, and CEC/stCEC levels in the < 28-day-old participants (neonates) were significantly low compared to those of the ≥ 28-day-old participants, indicating that the low CEC levels in the neonates depend on not only lower HDL-C but also lower HDL functionality. The low level of CEC/stCEC was remarkable in neonates born at < 34 weeks of gestation and did not improved to the reference level (1.000) until the infantile period. The relatively low or high CEC/stCEC ratios in neonates and infants were associated with lower or higher HDL-TG and HDL-TG/HDL-C ratio, respectively. However, no apparent effect of HDL-TG and HDL-TG/HDL-C ratio on CEC/stCEC was observed in the ≥ 1-year-old participants, indicating that HDL functionality in cholesterol efflux could be associated with the various HDL particles with various lipid compositions, but not just with HDL-TG and HDL-TG/HDL-C ratio.

5123 Remission of Antibodies Blocking the Insulin Receptor Reduces Atherogenicity of LDL Particles but Increases HDL Particle Atherogenicity

Abstract Disclosure: M. Hwang: None. R. Shamburek: None. M. Lightbourne: None. M. Sampson: None. A. Remaley: None. B. Abel: None. R.J. Brown: None. Background: Type B insulin resistance syndrome (TBIR) is a rare autoimmune disorder defined by the presence of autoantibodies against the insulin receptor, usually in the context of systemic autoimmune diseases such as lupus. In TBIR, insulin signaling is disrupted at the receptor-level, resulting in failure of insulin to both suppress hepatic glucose production and to stimulate de novo lipogenesis. This leads to a phenotype of extreme insulin resistance (IR) and hyperglycemia without dyslipidemia. IR and hyperglycemia resolve when remission of the autoantibody is induced by immunosuppression. Given the known association between IR and cardiovascular disease (CVD), we sought to compare biomarkers of CVD risk using lipoprotein particles measured by Nuclear Magnetic Resonance (NMR) in patients with TBIR during their active disease state vs remission. Methods: Patients with TBIR (N=14) had fasting labs including NMR lipoprotein profiles (analyzed using LP4 deconvolution algorithm) during active disease (positive antibodies to the insulin receptor and severe IR) and remission (defined by discontinuation of insulin or amelioration of hyperglycemia). Particle size (nm) and concentration of subclasses by size were measured for low-density lipoprotein (LDL) particles (nmol/L) and high-density lipoprotein (HDL) particles (umol/L). Results: Upon remission from TBIR, there were large decreases in hemoglobin A1c (from 10.9±3.0% to 6.1±1.1%, p&amp;lt;0.001) and insulin (from 1000.0 (715.9, 1000.0) mcU/mL to 16.8 (8.1, 39.2) mcU/mL, normal 2.6-24.9 mcU/mL, p&amp;lt;0.001), and increases in BMI (from 21.8±3.5 to 28.6±7.4 kg/m2, p&amp;lt;0.01), C3 (from 76±27 to 114±20 mg/dL, normal 82-185 mg/dL, p&amp;lt;0.01), and C4 (from 16±8 to 25±9 mg/dL, normal 15-53 mg/dL, p&amp;lt;0.01). After remission of TBIR, LDL profiles became less atherogenic: small LDL particle concentration decreased (from 523.4±170.2 to 362.8±119.7, normal 63.8-1719.6, p&amp;lt;0.01) and LDL particle size increased (from 20.6±0.5 to 21.2±0.3, normal 19.9 -21.6, p&amp;lt;0.01). By contrast, HDL profiles became more atherogenic after remission of TBIR: small HDL particle concentration increased (from 4.6±2.6 to 8.2±4.3, normal 6.6-19.3, p&amp;lt;0.01); the largest HDL particle concentration decreased (from 1.5±0.8 to 0.7±0.7, normal 0-1.2, p&amp;lt;0.01), and HDL particle size decreased (from 10.3±0.4 to 9.6±0.5, normal 8.4-9.9, p&amp;lt;0.001). Conclusions: Active TBIR is a pro-inflammatory state characterized by excess consumption of C3 and C4. Inflammation may contribute to an unfavorable LDL particle profile that improves after remission. However, lack of insulin signaling through the insulin receptor during active TBIR likely leads to an anti-atherogenic HDL profile that returns to normal levels when insulin signaling is restored after remission. Future studies will further investigate the role of insulin resistance and inflammation in CVD risk. Presentation: 6/3/2024

High-density lipoprotein over midlife and future cognition in women: The SWAN HDL ancillary study.

Limited data provides evidence-based insights on the association between comprehensive metrics of high-density lipoproteins (HDL) and cognitive performance, especially in midlife women for whom benefit might be the greatest. To assess the associations of serum HDL metrics including HDL lipid content [HDL cholesterol, phospholipid (HDL-PL), triglyceride], proteins/subclasses [apolipoprotein A-1 (apoA-1); small, medium, large, total HDL particle (HDL-P); and HDL size], and cholesterol efflux capacity with cognitive performance in midlife women. This prospective cohort study was conducted among 503 midlife women (1234 observations) from the Study of Women's Health Across the Nation HDL ancillary study. Joint models were applied to examine associations of HDL metrics assessed at midlife (50.2 ±2.9 years, baseline of the current study) and their changes over midlife (6.1 ±3.9 years of duration) with subsequent cognitive performance [working memory (Digit Span Backward Test), processing speed (Symbol Digit Modalities Test), and episodic memory immediate and delayed recall (East Boston memory test)] assessed repeatedly (maximum 5 times) 1.5 ±1 years later over 7.72 ± 4.10 years of follow up. Higher total HDL-P and smaller HDL size at midlife were associated with a better subsequent immediate recall, delayed recall and/or processing speed. Greater increase in HDL-PL, apoA-1, medium HDL-P, and total HDL-P and less increase in HDL size over midlife were associated with a better subsequent immediate and/or delayed recall. Enhancing specific serum HDL metrics during midlife could be promising in cognitive restoration, particularly memory, the initial and predominant symptom of Alzheimer's disease.

A-227 One Step Toward Implementation of Advanced Lipoprotien Testing in Children: A Pilot Study on Pediatric Reference Ranges

Abstract Background Abnormal serum lipid levels in childhood are associated with dyslipidemia and increased risk of cardiovascular disease in adulthood. High prevalence of childhood obesity in the US has increased concerns about the adverse effects of abnormal lipids in children, prompting recommendations for universal lipid screening in adolescents. While specialized analysis of lipoproteins by nuclear magnetic resonance (NMR) has been predominately used in adults with risk factors for CVD, our laboratory also receives pediatric samples for NMR testing, most commonly associated with diagnostic codes for hyperlipidemia and/or abnormal weight gain. Currently adult-based reference ranges for the NMR lipoprotein measurements are used in children. The objective of this pilot study was to compare lipoprotein profiles of healthy adults and children and to assess the impact of reference intervals for children on clinical interpretation of pediatric results. Methods Serum samples were collected from 60 healthy children, ages 1 - 17 years, and 148 self-identified healthy adults, ages 19 - 64 years old. NMR lipoprotein analysis was performed using the Axinon lipoFIT by NMR assay on a 600 MHz NMR (Bruker). Statistical analysis was conducted in Excel and Graph Pad Prism. Reference intervals (RIs) were determined in EP Evaluator as the central 95% interval. Results The levels of atherogenic low-density lipoprotein particle number (LDL-P) and small LDL-P (sLDL-P) were significantly lower in children compared to adults: 783±222 vs 1212±412 nmol/L and 302±142 vs 498±306 nmol/L, respectively (p&amp;lt;0.00001). Additionally, LDL size (LDL-s) was significantly larger in children than adults (21.23±0.29 vs 21.06±0.44 nm, p=0.006), reflecting prevalence of less dense LDL-P in the former group. Pediatric samples also had lower number of anti-atherogenic high-density lipoprotein particles (HDL-P) compared to adults: 29.4±4.6 vs 33.5±4.6 µmol/L, p&amp;lt;0.00001. The significant differences in the number and size of lipoprotein particles between adults and children implies that currently used adult reference intervals might not be appropriate for evaluating pediatric NMR samples. Therefore, we estimated RIs for our heathy pediatric and adult cohorts and applied these RIs to our retrospective data of 618 samples from children 1-17 years old, which were submitted for NMR lipoprotein testing in recent years. The analysis showed that using the adult RIs, 37% and 27% of pediatric samples would not flag for abnormally elevated LDL-P and sLDL-P, respectively; but they would be flagged based on the RI derived from our pediatric cohort. Moreover, 12% pediatric samples flagged for low HDL-P would have normal HDL-P levels if pediatric RIs are used instead of adult RIs. Conclusions Use of adult reference intervals in children may result in misclassification of lipid status and underestimation or overestimation of dyslipidemia and CVD risk in children. This pilot study highlights the need for pediatric reference intervals to guide interpretation of advanced lipid testing in children.