LDL Subfractions Research Articles

The Impact of Atorvastatin Treatment on the Distribution of Low-Density Lipoprotein Subfractions and the Level of Vitamin D in Patients After Acute Myocardial Infarction: Preliminary Findings

Clinical trial results indicate that statin therapy aimed at normalising the lipid profile can prevent and reduce the risk of cardiovascular events. Both LDL and HDL consist of several subfractions, with only the smallest and densest subfractions being the most atherogenic. We examine the effect of Atorvastatin treatment not only on basic lipid profile parameters but also atherogenic lipoprotein subfractions and 25(OH)D levels in patients after the first acute myocardial infarction. The study population had not previously received lipid-lowering medications. Serum 25(OH)D concentration was determined by direct competitive immunochemiluminescent assays. Lipoprotein subfractions, including VLDL, IDL-C, IDL-B, and IDL-A, as well as LDL1, LDL2 (large LDL), and LDL3-7 (sdLDL), were measured in serum (Lipoprint® system). Almost all patients had 25(OH)D deficiency. Atorvastatin primarily reduced strongly atherogenic sdLDL and decreased the less atherogenic large LDL subfractions. A statistically significant reduction in VLDL cholesterol and IDL fractions was also observed. Analysing LDL subfractions provides a more detailed insight into lipid metabolism and enables the identification of patients with a more atherogenic phenotype. LDL subfractions may thus become not only more accurate prognostic biomarkers but also targets for lipid-lowering therapy. Vitamin D deficiency is associated with atherogenic dyslipidaemia, particularly high levels of sdLDL.

Clinical prediction of wound re-epithelisation outcomes in non-severe burn injury using the plasma lipidome

Whilst wound repair in severe burns has received substantial research attention, non-severe burns (<20% total body surface area) remain relatively understudied, despite causing considerable physiological impact and constituting most of the hospital admissions for burns. Early prediction of healing outcomes would decrease financial and patient burden, and aid in preventing long-term complications from poor wound healing. Lipids have been implicated in inflammation and tissue repair and may play essential roles in burn wound healing. In this study, plasma samples were collected from 20 non-severe burn patients over 6 weeks from admission, including surgery, and analysed by liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy to detect 850 lipids and 112 lipoproteins. Orthogonal projections to latent structures-discriminant analysis was performed to identify changes associated with re-epithelialisation and delayed re-epithelisation.We demonstrated that the lipid and lipoprotein profiles at admission could predict re-epithelisation outcomes at 2 weeks post-surgery, and that these discriminatory profiles were maintained up to 6 weeks post-burn. Inflammatory markers GlycB and C-reactive protein indicated divergent systemic responses to the burn injury at admission. Triacylglycerols, diacylglycerols and low-density lipoprotein subfractions were associated with delayed wound closure (p-value <0.02, Cliff’s delta >0.7), whilst high-density lipoprotein subfractions, phosphatidylinositols, phosphatidylcholines, and phosphatidylserines were associated with re-epithelisation at 2 weeks post-surgery (p-value <0.01, Cliff’s delta <-0.7). Further model validation will potentially lead to personalised intervention strategies to reduce the risk of chronic complications post-burn injury.

ADLM Guidance Document on the Measurement and Reporting of Lipids and Lipoproteins.

The accurate measurement of blood lipids and lipoproteins is crucial for the clinical management of atherosclerotic disease risk. Despite progress in standardization, there are still significant variations in pre-analytical requirements, methods, nomenclature, and reporting work flows. The guidance document aims to improve standardization of clinical lipid testing work flows. It provides recommendations for the components of the lipid panel, fasting requirements, reporting of results, and specific recommendations for non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL-C), lipoprotein(a) [Lp(a)], apolipoprotein B (apo B), point-of-care lipid testing, and LDL subfraction testing. Lipid panels should always report non-HDL-C and LDL-C calculations if possible. Fasting is not routinely required except in specific cases. Modern equations should be utilized for LDL-C calculation. These equations allow for LDL-C reporting at elevated concentrations of triglycerides and obviate the need for direct measured LDL-C in most cases.

Variation of LDL cholesterol in response to the replacement of saturated with unsaturated fatty acids: a nonrandomized, sequential dietary intervention; the Reading, Imperial, Surrey, Saturated fat Cholesterol Intervention (“RISSCI”-1) study

BackgroundSerum low density lipoprotein (LDL) cholesterol shows marked interindividual variation in response to the replacement of saturated fatty acids (SFAs) with unsaturated fatty acids (UFAs). ObjectivesTo demonstrate the efficacy of United Kingdom guidelines for exchanging dietary SFAs for UFAs, to reduce serum LDL cholesterol and other cardiovascular disease (CVD) risk factors, and to identify determinants of the variability in LDL cholesterol response. MethodsHealthy males (n = 109, mean ± SD age 48 ± 11 y; BMI 25.1 ± 3.3 kg/m2), consumed a higher-SFA/lower-UFA diet for 4 wk, followed by an isoenergetic, lower-SFA/higher-UFA diet for 4 wk (achieved intakes SFA:UFA as % total energy 19.1:14.8 and 8.9:24.5, respectively). Serum LDL cholesterol, CVD risk markers, peripheral blood mononuclear cell (PBMC) gene expression, and dietary intakes were assessed at baseline and the end of each diet. ResultsTransition from a higher-SFA/lower-UFA to a lower-SFA/higher-UFA diet significantly reduced fasting blood lipids: LDL cholesterol (−0.50 mmol/L; 95% confidence interval [CI]: −0.58, −0.42), high-density lipoprotein (HDL) cholesterol (−0.11 mmol/L; 95% CI: −0.14, −0.08), and total cholesterol (TC) (−0.65 mmol/L; 95% CI:−0.75, −0.55). The dietary exchange also reduced apolipoprotein (apo)B, TC:HDL cholesterol ratio, non-HDL cholesterol, E-selectin (P < 0.0001), and LDL subfraction composition (cholesterol [LDL-I and LDL-II], apoB100 [LDL-I and LDL-II], and TAG [LDL-II]) (P < 0.01). There was also an increase in plasma biomarkers of cholesterol intestinal absorption (β-sitosterol, campesterol, cholestanol), and synthesis (desmosterol) (P < 0.0001) and fold change in PBMC LDL-receptor mRNA expression relative to the higher-SFA/lower-UFA diet (P = 0.035). Marked interindividual variation in the change in serum LDL cholesterol response (−1.39 to +0.77 mmol/L) to this dietary exchange was observed, with 33.7% of this variation explained by serum LDL cholesterol before the lower-SFA/higher-UFA diet and reduction in dietary SFA intake (adjusted R2 27% and 6.7%, respectively). APOE genotype was unrelated to serum LDL cholesterol response to SFA. ConclusionsThese findings support the efficacy of United Kingdom SFA dietary guidelines for the overall lowering of serum LDL cholesterol but showed marked variation in LDL cholesterol response. Further identification of the determinants of this variation will facilitate targeting and increasing the efficacy of these guidelines.The RISSCI-1 study was registered with ClinicalTrials.Gov (No. NCT03270527).

Nutritional effect on lipoproteins and their subfractions in patients with Psoriatic Arthritis: a 12-week randomized trial—the DIETA trial

IntroductionPatients with psoriatic arthritis have some lipid metabolism changes and higher risk of metabolic syndrome (MetS) and cardiovascular diseases, regardless of traditional risk factors, suggesting that chronic inflammation itself plays a central role concerning the atherosclerosis. However, there is a lack of information regarding atherogenic pattern and lipoprotein subfractions burden in these individuals.AimTo evaluate the HDL and LDL-cholesterol plasmatic levels and their subfractions after a nutritional intervention in patients with psoriatic arthritis (PsA).MethodsThis was a randomized, placebo-controlled clinical trial of a 12-week nutritional intervention. PsA patients were randomly assigned to 1-Placebo: 1 g of soybean oil daily, no dietetic intervention; 2-Diet + Supplementation: an individualized diet, supplemented with 604 mg of omega-3 fatty acids, three times a day; and 3-Diet + Placebo: individualized diet + 1 g of soybean oil. The LDL subfractions were classified as non-atherogenic (NAth), atherogenic (Ath) or highly atherogenic (HAth), whereas the HDL subfractions were classified as small, medium, or large particles, according to the current recommendation based on lipoproteins electrophoresis.ResultsA total of 91 patients were included in the study. About 62% of patients (n = 56) had an Ath or HAth profile and the main risk factors associated were male gender, longer skin disease duration and higher BMI. Thirty-two patients (35%) had a high-risk lipoprotein profile despite having LDL plasmatic levels below 100 mg/dL. The 12-week nutritional intervention did not alter the LDL subfractions. However, there were significant improvement of HDL subfractions.ConclusionRecognizing the pro-atherogenic subfractions LDL pattern could be a relevant strategy for identifying PsA patients with higher cardiovascular risk, regardless total LDL plasmatic levels and disease activity. In addition, a short-term nutritional intervention based on supervised and individualized diet added to omega-3 fatty acids changed positively the HDLLARGE subfractions, while LDLLARGE subfraction was improved in hypercholesterolemic individuals.ClinicalTrials.gov identifier: NCT03142503 (http://www.clinicaltrials.gov/).

The serum metabolomic profiles of atrial fibrillation patients treated with direct oral anticoagulants or vitamin K antagonists

AimsLong-term oral anticoagulation is the primary therapy for preventing ischemic stroke in patients with atrial fibrillation (AF). Different types of oral anticoagulant drugs can have specific effects on the metabolism of patients. Here we characterize, for the first time, the serum metabolomic and lipoproteomic profiles of AF patients treated with anticoagulants: vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). Materials and methodsSerum samples of 167 AF patients (median age 78 years, 62 % males, 70 % on DOACs treatment) were analyzed via high resolution 1H nuclear magnetic resonance (NMR) spectroscopy. Data on 25 metabolites and 112 lipoprotein-related fractions were quantified and analyzed with multivariate and univariate statistical approaches. Key findingsOur data provide evidence that patients treated with VKAs and DOACs present significant differences in their profiles: lower levels of alanine and lactate (odds ratio: 1.72 and 1.84), free cholesterol VLDL-4 subfraction (OR: 1.75), triglycerides LDL-1 subfraction (OR: 1.80) and 4 IDL cholesterol fractions (ORs ∼ 1.80), as well as higher levels of HDL cholesterol (OR: 0.48), apolipoprotein A1 (OR: 0.42) and 7 HDL cholesterol fractions/subfractions (ORs: 0.40–0.51) are characteristic of serum profile of patients on DOACs' therapy. SignificanceOur results support the usefulness of NMR-based metabolomics for the description of the effects of oral anticoagulants on AF patient circulating metabolites and lipoproteins. The higher serum levels of HDL cholesterol observed in patients on DOACs could contribute to explaining their reduced cardiovascular risk, suggesting the need of further studies in this direction to fully understand possible clinical implications.

Atherogenic plasma index is associated with ischemıc cerebrovascular events due to carotid artery disease

Aims: Low molecular weight lipoprotein (LDL) and triglyceride (Tg), among cardiovascular disease risk factors, are replaced by markers with higher sensitivity and specificity. The atherogenic plasma index (API) has a strong predictive power for cardiovascular diseases. In our study, we aimed to compare the predictive power of API and other lipid parameters in detecting carotid artery disease (CAS) in patients with ischemic stroke. Methods: A total of 878 individuals were analyzed, and 583 patients with ischemic stroke were enrolled in this study. The patients were divided into two groups according to the presence or absence of carotid artery disease in the Doppler ultrasound examination. Demographic data and lipid parameters were compared between both groups. Results: The mean age of the patients with CAS was statistically significantly higher than the other group (74.33±11.27 vs 70.11±13.57; p=0.002). The Tg/HDL ratio was higher in patients with CAS than those without (3.80±2.83 vs 3.69±2.57; p=0.048). API was found to be statistically significantly higher in the group of patients with CAS compared to the other group (0.67±0.32 vs 0.48±0.25; p=0.024). Tg/HDL ratio and API were determined as predictive parameters for CAS in patients with ischemic cerebrovascular stroke. [OR: 1.345 (0.712-1.437); p=0.048, OR: 7.21 (0.881-8.056); p=0.023]. Conclusion: Conflicting results regarding the relation between atherosclerosis and conventional lipid parameters led to more specific subgroups being investigated. API shows a good correlation with the highly sensitive LDL subfraction in terms of atherosclerosis. API is a feasible variable predicting the presence of CAS in patients with ischemic stroke.

Effects of phytosterol supplementation on lipoprotein subfractions and LDL particle quality

Phytosterols are natural components of plant-based foods used as supplements because of their known cholesterol-lowering effect. However, their effects on lipoprotein subfractions and the quality of the LDL particle have not been studied in greater detail. We aimed to evaluate the effects of phytosterols supplements on lipids, lipoproteins subfractions, and on the quality of LDL. A prospective, pilot-type, open label, cross-over study, randomized 23 males in primary prevention of hypercholesterolemia to receive diet or diet plus phytosterol (2.6 g in 2 doses, with meals) for 12 weeks, when treatments were switched for another 12 weeks. Lipoprotein subfractions were analyzed by electrophoresis in polyacrylamide gel (Lipoprint System®). The Sampson equation estimated the small and dense (sd) and large and buoyant (lb) LDL subfractions from the lipid profile. Quality of LDL particle was analyzed by Z-scan and UV–vis spectroscopy. Primary outcome was the comparison of diet vs. diet plus phytosterols. Secondary outcomes assessed differences between baseline, diet and diet plus phytosterol. Non-parametric statistics were performed with p < 0.05. There was a trend to reduction on HDL-7 (p = 0.05) in diet plus phytosterol arm, with no effects on the quality of LDL particles. Heatmap showed strong correlations (ρ > 0.7) between particle size by different methods with both interventions. Diet plus phytosterol reduced TC, increased HDL-c, and reduced IDL-B, whereas diet increased HDL7, and reduced IDL-B vs. baseline (p < 0.05, for all). Phytosterol supplementation demonstrated small beneficial effects on HDL-7 subfraction, compared with diet alone, without effects on the quality of LDL particles.This trial is registered in Clinical Trials (NCT06127732) and can be accessed at https://clinicaltrials.gov.

Obesity and Sex as Determinants of Atherogenic Risk Associated with High-Density (HDL) and Low-Density Lipoprotein (LDL) Subfractions in Adolescents: A Population-based Study Based on Health Survey of Sao Paulo

Background: Worldwide, obesity in adolescents is an epidemiological concern. Overweight and obesity are associated with comorbidities in adult life, such as increased risk of hypertension and other non-communicable diseases. This study investigated possible differences between traditional lipid markers and Low-Density Lipoprotein (LDL) and High-Density Lipoprotein (HDL) subfractions in a population-wide representative sample of Brazilian adolescents. Methods: The individuals included in the study comprise a subsample of the 2015 Health Survey of São Paulo (ISA-Capital 2015). LDL and HDL particle sizes were determined by the Lipoprint® System (Quantimetrix Corporation). Results: 272 Brazilian adolescents with a mean age of 15.2 ± 2.2 years, of which 47.8% (n = 130) are boys. Analysis of LDL subfractions showed an increase in LDL 2 content in girls (5.7% vs. 5.1%; p = 0.047). This result was associated with a higher content of large LDL in girls (17.8% vs. 13.5%; p &lt; 0.001) and a significant, lower content of small LDL (1.7% vs. 3.4%; p = 0.002). When obesity was considered, we observed that regardless of being overweight, girls had higher large and small LDL than boys. However, when a large to small LDL ratio was calculated, girls with no excess weight had higher values than boys with no excess weight (10.6 vs. 9.3; p = 0.038), and these had lower LDL ratio than overweight boys (9.3 vs. 13.5; p = 0.016). On the other hand, boys had higher HDL 2 content than girls (8.9% vs. 8.0%; p = 0.017), which was associated with increased large HDL values in boys (1.9% vs. 1.7%; p = 0.047). Regression analysis was performed according to gender, the sum of very low-density lipoprotein (VLDL) + intermediate density lipoprotein (IDL) C + IDL B subfractions was adjusted for age and body mass index (BMI), showing that girls had lower atherogenic lipid profile (β = 0.987; CI = 0.977-0.998; p = 0.017) than boys. When the regression analysis was performed according to BMI, large LDL in adolescents with no excess weight presented a lower atherogenic lipid profile (β = 1.040; CI = 1.000-1.082; p = 0.049), adjusted for age and sex, than overweight adolescents. Conclusion: Regardless of excess weight, girls showed a cardioprotective profile more associated with a favorable distribution of LDL subfractions than boys, reinforcing the relevance of evaluating qualitative aspects of lipoproteins in addition to the traditional cholesterol content.

Effects of portable pedal machines at work on lipoprotein subfraction profile in sedentary workers – the REMOVE study

BackgroundSedentary behaviour at work is a major cause of atherosclerosis, particularly in tertiary workers. However, no studies have ever assessed the effect of active workstation on lipoprotein subfraction profile. This study aimed to evaluate the effect of 12-week portable pedal machines (PPMs) on lipoprotein subfraction profile among healthy sedentary workers.MethodsHealthy administrative workers were randomized into an intervention group using PPMs for 12 weeks or a control group using normal-desk. Lipoprotein subfractions were assessed using Lipoprint® electrophoresis. Main outcomes were explored using mixed models with sensitivity analyses (four models).ResultsWe included 40 participants (43.7 ± 8.6 years old, 100% women, BMI 23.8 ± 3.4 kg/m2; sedentary time at work 7.7 ± 1.8 h/day). Groups did not differ at baseline in any outcomes. 32 participants finished the trial. Changes in lipoprotein subfractions were especially marked for LDL profile. There was an interaction time x group for all parameters related to LDL and their subfractions: total LDL-cholesterol (p = 0.012), LDL particle size (p = 0.027), large LDL subfractions 1 and 2 (p = 0.001), and small dense LDL subfractions 3 to 7 (p = 0.046), using the crude model. The interaction reflects difference in the direction of changes between groups. The LDL particle size significantly increased in the intervention group (from 271.9 ± 2.5 at t0 to 272.8 ± 1.9 Ångström at t1, p = 0.037) while it did not change in the control group (272.5 ± 1.7 at t0 to 271.8 ± 1.5Å at t1, p = 0.52). All interactions were constantly significant whatever the models. Influencing variables were mainly stress at work that was associated with an increase in total LDL-cholesterol (coefficient 3.15, 95CI 0.20 to 6.11 mg/dl, p = 0.038), and BMI that was associated with Large-LDL, Large-HDL, IDL-C and triglycerides.ConclusionsLipoprotein profile was improved after a 12-week PPMs intervention at work in healthy administrative workers. Changes were mainly showed for LDL and LDL subfractions. Lipoprotein profile was worsened by stress at work, BMI and age.Trial registrationNCT04153214.

Relevance of plasma lipoproteins and small metabolites in assessment of nutritional status among patients with severe injuries

BackgroundThis study aimed to identify plasma lipoproteins and small metabolites associated with high risk of malnutrition during intensive care unit (ICU) stay in patients with severe injuries. MethodsThis observational prospective exploratory study was conducted at two level-1 trauma centers in the Netherlands. Adult patients (aged ≥18 years) who were admitted to the ICU for more than 48 h between July 2018 and April 2022 owing to severe injuries (polytrauma, as defined by Injury Severity Scores of ≥16) caused by blunt trauma were eligible for inclusion. Partial least squares discriminant analysis was used to analyze the relationship of 112 lipoprotein-related components and 23 small metabolites with the risk of malnutrition (modified Nutrition Risk in Critically Ill score). Malnutrition was diagnosed based on Subjective Global Assessment scores. The relationship of lipoprotein properties and small metabolite concentrations with malnutrition (during ICU admission) was evaluated using mixed effects logistic regression. ResultsOverall, 51 patients were included. Lower (very) low-density lipoprotein ([V]LDL) (free) cholesterol and phospholipid levels, low particle number, and higher levels of LDL triglycerides were associated with a higher risk of malnutrition (variable importance in projection [VIP] value >1.5). Low levels of most (V)LDL and intermediate-density lipoprotein subfractions and high levels of high-density lipoprotein Apo-A1 were associated with the diagnosis of malnutrition (VIP value >1.5). Increased levels of dimethyl sulfone, trimethylamine N-oxide, creatinine, N, N-dimethylglycine, and pyruvic acid and decreased levels of creatine, methionine, and acetoacetic acid were also indicative of malnutrition (VIP value >1.5). Overall, 14 lipoproteins and 1 small metabolite were significantly associated with a high risk of malnutrition during ICU admission (P <0.05); however, the association did not persist after correcting the false discovery rate (P=0.35 for all). ConclusionIncreased triglyceride in several lipoprotein subfractions and decreased levels of other lipoprotein subfraction lipids and several small metabolites (involved in the homocysteine cycle, ketone body formation, and muscle metabolism) may be indicative of malnutrition risk. Following validation in larger cohorts, these indicators may guide institution of preventive nutritional measures in patients admitted to the ICU with severe injuries.

Diverse impacts of red palm olein, extra virgin coconut oil and extra virgin olive oil on cardiometabolic risk markers in individuals with central obesity: a randomised trial.

Dietary fats with an abundance of phytonutrients have garnered public attention beyond fatty acids per se. This study was set to investigate the impact of consuming diets with red palm olein (RPOO), extra virgin coconut oil (EVCO) and extra virgin olive oil (EVOO, as a control) on cardiometabolic risk biomarkers and lipid profile. We recruited a total of 156 individuals with central obesity, aged 25-45years, with waist circumference ≥ 90cm for men and ≥ 80cm for women in a parallel single-blind 3-arm randomised controlled trial. The participants consumed isocaloric diets (~ 2400kcal) enriched with respective test fats (RPOO, EVCO or EVOO) for a 12-week duration. The mean of the primary outcome plasma high sensitivity C-reactive protein was statistically similar between the three diets after a 12-week intervention. EVOO resulted in significantly lower mean LDL cholesterol compared with RPOO and EVCO, despite similar effects on LDL and HDL cholesterol subfractions. The RPOO diet group showed elevated mean and -carotenes levels compared with EVCO and EVOO diet groups (P < 0.05), corresponding with the rich carotenoid content in RPOO. The three oils, each of which has unique phytonutrient and fatty acid compositions, manifested statistically similar cardiometabolic effects in individuals with central obesity at risk of developing cardiovascular diseases with distinct circulating antioxidant properties. ClinicalTrials.gov (NCT05791370).

The Interplay of Dyslipidemia, Oxidative Stress, and Clinical Outcomes in Acute Ischemic Stroke Patients with and without Coronary Artery Disease.

We assessed lipid and lipoprotein profiles, along with oxidative stress (OS) parameters, in patients within the crucial 24 h period following an acute ischemic stroke (AIS), comparing those with and without coronary artery disease (CAD). We aimed to correlate these measures with clinical condition scales (NIHSS, mRS) post-AIS. This study included 27 AIS patients without CAD (AIS group) and 37 AIS patients with CAD (CAD-AIS group). Using polyacrylamide gel electrophoresis (Lipoprint system), we determined plasma LDL and HDL subfractions. Spectrophotometric methods were used to assess plasma antioxidant capacity, lipoperoxides, homocysteine (HC) levels, paraoxonase1, and catalase activities. We also measured urine isoprostanes and the activities of antioxidant enzymes (SOD, GPx) with commercial kits. CAD-AIS patients had notably higher HC levels, while there were no significant differences in lipoprotein subfractions and OS parameters between both groups. In the AIS group, mRS scores showed negative correlations with catalase, GPx activities, and total cholesterol. In the CAD-AIS group, atherogenic lipoproteins (IDLC, LDL2, LDL3-7) exhibited a significant positive correlation with mRS. This study underscores the role of dyslipidemia and OS in the development of AIS and CAD. It emphasizes the complex connections between specific biomarkers and post-stroke clinical outcomes. Our results suggest a significant impact of CAD treatment on lipid profile but not on homocysteine levels. The traditional narrative associating high cholesterol as the ultimate risk factor for cardiovascular diseases needs to be challenged, at least with respect to neurological outcomes. These insights may guide more targeted therapeutic approaches.

New Advances in Rapid Pretreatment for Small Dense LDL Cholesterol Measurement Using Shear Horizontal Surface Acoustic Wave (SH-SAW) Technology.

Atherosclerosis is an inflammatory disease of the arteries associated with alterations in lipid and other metabolism and is a major cause of cardiovascular disease (CVD). LDL consists of several subclasses with different sizes, densities, and physicochemical compositions. Small dense LDL (sd-LDL) is a subclass of LDL. There is growing evidence that sd-LDL-C is associated with CVD risk, metabolic dysregulation, and several pathophysiological processes. In this study, we present a straightforward membrane device filtration method that can be performed with simple laboratory methods to directly determine sd-LDL in serum without the need for specialized equipment. The method consists of three steps: first, the precipitation of lipoproteins with magnesium harpin; second, the collection of effluent from a 100 nm filter; and third, the quantification of sd-LDL-ApoB in the effluent with an SH-SAW biosensor. There was a good correlation between ApoB values obtained using the centrifugation (y = 1.0411x + 12.96, r = 0.82, n = 20) and filtration (y = 1.0633x + 15.13, r = 0.88, n = 20) methods and commercially available sd-LDL-C assay values. In addition to the filtrate method, there was also a close correlation between sd-LDL-C and ELISA assay values (y = 1.0483x - 4489, r = 0.88, n = 20). The filtration treatment method also showed a high correlation with LDL subfractions and NMR spectra ApoB measurements (y = 2.4846x + 4.637, r = 0.89, n = 20). The presence of sd-LDL-ApoB in the effluent was also confirmed by ELISA assay. These results suggest that this filtration method is a simple and promising pretreatment for use with the SH-SAW biosensor as a rapid in vitro diagnostic (IVD) method for predicting sd-LDL concentrations. Overall, we propose a very sensitive and specific SH-SAW biosensor with the ApoB antibody in its sensitive region to monitor sd-LDL levels by employing a simple delay-time phase shifted SH-SAW device. In conclusion, based on the demonstration of our study, the SH-SAW biosensor could be a strong candidate for the future measurement of sd-LDL.

Protective effect of phospholipids in lipoproteins against diabetic kidney disease: A Mendelian randomization analysis.

The etiology of diabetic kidney disease is complex, and the role of lipoproteins and their lipid components in the development of the disease cannot be ignored. However, phospholipids are an essential component, and no Mendelian randomization studies have yet been conducted to examine potential causal associations between phospholipids and diabetic kidney disease. Relevant exposure and outcome datasets were obtained through the GWAS public database. The exposure datasets included various phospholipids, including those in LDL, IDL, VLDL, and HDL. IVW methods were the primary analytical approach. The accuracy of the results was validated by conducting heterogeneity, MR pleiotropy, and F-statistic tests. MR-PRESSO analysis was utilized to identify and exclude outliers. Phospholipids in intermediate-density lipoprotein (OR: 0.8439; 95% CI: 0.7268-0.9798), phospholipids in large low- density lipoprotein (OR: 0.7913; 95% CI: 0.6703-0.9341), phospholipids in low- density lipoprotein (after removing outliers, OR: 0.788; 95% CI: 0.6698-0.9271), phospholipids in medium low- density lipoprotein (OR: 0.7682; 95% CI: 0.634-0.931), and phospholipids in small low-density lipoprotein (after removing outliers, OR: 0.8044; 95% CI: 0.6952-0.9309) were found to be protective factors. This study found that a higher proportion of phospholipids in intermediate-density lipoprotein and the various subfractions of low-density lipoprotein, including large LDL, medium LDL, and small LDL, is associated with a lower risk of developing diabetic kidney disease.

High-density lipoprotein cholesterol subfraction HDL2 is associated with improved endothelial function in systemic lupus erythematosus

ObjectivePatients with systemic lupus erythematosus (SLE) have increased risk of premature atherosclerosis but the exact mechanisms remains unclear. Flow-mediated dilatation (FMD) is an established non-invasive assessment of vascular endothelial function....

The association of Sort1 expression with LDL subfraction and inflammation in patients with coronary artery disease

Background Controversial effect of sortilin on lipoprotein metabolism in the development of atherosclerosis reveals the need for more extensive research Objectives The aim of this study was to investigate the association between Sort1 gene expression and lipids, lipoprotein subfractions, and inflammation in CAD. Methods The study population included 162 subjects with CAD and 49 healthy individuals. The Sort1 gene expression level was determined by qRT-PCR using Human Sortilin TaqMan Gene Expression Assays. Lipoprotein subclasses were analysed by the Lipoprint system. Serum levels of apolipoprotein and CRP were measured by autoanalyzer. Results Sort1 gene expression and atherogenic subfraction (SdLDL) levels were significantly higher (p < 0.001) while atheroprotective subfraction (LbLDL) was lower in the subjects with CAD (p < 0.050). Also, increased Sort1 gene expression levels were observed in those with higher CRP values. Conclusions Our findings reveal that the high Sort1 gene expression has a prominent linear relationship with both the atherogenic LDL phenotype and proinflammation, thereby might contribute to the occurrence of CAD.

Self-Association of Von Willebrand Factor (VWF) into Prothrombotic Fibers Is Most Potently Enhanced By the Highly Atherogenic Small, Dense Fraction of Low-Density Lipoprotein (sd-LDL)

We recently demonstrated that plasma lipoproteins play a major role in regulating the function of the hemostatic system by either inhibiting or promoting the self-association of von Willebrand factor (VWF) into large fibers and bundles that are hyperadhesive for platelets. Such fibers can form on the surface of activated endothelium such as during thrombotic microangiopathies. We showed that high-density lipoprotein (HDL) attenuates VWF self-association and reduces the formation of VWF-platelet thrombi, both in vitro and in mice (PMID:26552698). By contrast, low-density lipoprotein (LDL) enhances VWF self-association and promotes the formation of VWF-platelet thrombi ( Blood, in press). Consequently, wild-type mice with elevated plasma LDL display intense and prolonged VWF-platelet thrombosis in stimulated mesenteric microvessels, exceeding even the thrombosis observed in ADAMTS13-deficient mice with normal LDL levels. All the lipoproteins of low density carry apolipoprotein (apo) B100 and comprise fractions of very low density (VLDL), intermediate density (IDL), and low density (LDL). The LDL fraction comprises two subfractions: small-dense (sd) LDL and large-buoyant (lb) LDL. Epidemiologic studies suggest that sd-LDL is the most atherogenic subfraction (PMID:33586462). Another atherogenic lipoprotein also carries apoB-100, Lp(a), in which the apoB-100 is complexed with apo(a). Here, we sought to determine the effect of LDL subfraction(s) on VWF self-association. We isolated LDL, sd-LDL and lb-LDL from healthy donor plasma by sequential KBr density centrifugation. Lp(a) was purified from patients with high circulating Lp(a) (&amp;gt;50 mg/dL) as described by Mueller et al. (PMID:35650291). We first tested these lipoproteins in microfluidic devices adapted from the design of Herbig and Diamond (PMID:26178390). In these devices, high shear stress and flow acceleration are generated around a 30-um-wide pillar within a 60-um-wide flow channel and induce the attachment and self-association of VWF into fibers on and around the pillar. We quantified VWF fiber accumulation from differential interference contrast (DIC) images. Of all the lipoprotein fractions, sd-LDL was the most potent in accelerating VWF strand accumulation (see figure). The effect of lipoproteins in this device correlated with their impact on microvascular thrombosis in vivo. We infused apoB100-containing lipoproteins into wild-type mice (3-4 weeks old) before inducing VWF-platelet thrombi deposition in the mesenteric microvasculature with ionophore. All the apoB100 lipoproteins enhanced microvascular thrombosis [we did not test Lp(a), which had no effect in the microfluidic channel], but sd-LDL was by far the most potent; the treated mice had twice the number of large thrombi (&amp;gt;30-um diameter) as the mice treated with an equivalent quantity of lb-LDL. The effect also persisted for much longer before returning to baseline with the sd-LDL. We have explored possible reasons why sd-LDL is so much more potent. Compared to the other apoB-containing lipoproteins, sd-LDL is smaller and denser, with a greater surface curvature. Whether this fact changes accessibility to sites on apoB100 is not known. We also compared the lipidomes and proteomes of sd-LDL and lb-LDL for clues to the difference. Compared to lb-LDL, sd-LDL contained a much higher content of cholesterol and cholesterol esters per particle. The proteomes of the two particles were also different, with several proteins being more abundant in lb-LDL, in particular apoC-III, apoE, apoA-IV, and apoC-II. Only apoF was significantly more abundant in sd-LDL. We are currently testing to determine if any of these difference accounts for the differences between the two LDL subfractions in promoting VWF self-association. In summary, we show that the lipoprotein associated with the greatest atherosclerotic burden and most cardiovascular disease is also the one with the most potent effect in promoting a prothrombotic state by enhancing VWF self-association. These findings have important implications for the development of the atherosclerotic lesion, the formation of the thrombus after the lesion ruptures, and for the microvascular dysfunction often observed after revascularization.

Gender-Dependent Associations between Serum Betatrophin Levels and Lipoprotein Subfractions in Diabetic and Nondiabetic Obese Patients.

Betatrophin, also known as angiopoietin-like protein 8 (ANGPTL8), mainly plays a role in lipid metabolism. To date, associations between betatrophin and lipoprotein subfractions are poorly investigated. For this study, 50 obese patients with type 2 diabetes (T2D) and 70 nondiabetic obese (NDO) subjects matched in gender, age, and body mass index (BMI) as well as 49 gender- and age-matched healthy, normal-weight controls were enrolled. Serum betatrophin levels were measured with ELISA, and lipoprotein subfractions were analyzed using Lipoprint gel electrophoresis. Betatrophin concentrations were found to be significantly higher in the T2D and NDO groups compared to the controls in all subjects and in females, but not in males. We found significant positive correlations between triglyceride, very low density lipoprotein (VLDL), large LDL (low density lipoprotein), small LDL, high density lipoprotein (HDL) -6-10 subfractions, and betatrophin, while negative correlations were detected between betatrophin and IDL, mean LDL size, and HDL-1-5. Proportion of small HDL was the best predictor of betatrophin in all subjects. Small LDL and large HDL subfractions were found to be the best predictors in females, while in males, VLDL was found to be the best predictor of betatrophin. Our results underline the significance of serum betatrophin measurement in the cardiovascular risk assessment of obese patients with and without T2D, but gender differences might be taken into consideration.

Association of LDL-cholesterol subfractions with cardiovascular disorders: a systematic review

BackgroundCardiovascular disorders (CVDs) are the leading cause of death worldwide. This study aimed to evaluate the association between low-density lipoprotein (LDL) subfractions and cardiovascular disorders.MethodsTo ensure the rigor of the systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. For this systematic review, a comprehensive search strategy was performed in important databases including PubMed, Scopus, Embase, International Statistical Institute (ISI) Web of Science, and google scholar from 2009 to February 2021. The following terms were used for systematic search: low-density lipoprotein, LDL, subfractions, subclasses, nuclear magnetic resonance, NMR, chromatography, high-pressure liquid, HPLC, cardiovascular disease, cerebrovascular, and peripheral vascular disease. Also, for evaluating the risk of bias, the Newcastle-Ottawa scale was employed.ResultsAt the end of the search process, 33 articles were included in this study. The results of most of the evaluated studies revealed that a higher LDL particle number was consistently associated with increased risk for cardiovascular disease, independent of other lipid measurements. Also, small dense LDL was associated with an increased risk of CVDs. There was no association between LDL subfraction and CVDs in a small number of studies.ConclusionsOverall, it seems that the evaluation of LDL subclasses can be used as a very suitable biomarker for the assessment and diagnosis of cardiovascular diseases. However, further studies are required to identify the mechanisms involved.