Apolipoprotein Concentrations Research Articles

Worldwide Increasing Use of Nonfasting Rather Than Fasting Lipid Profiles.

Historically, lipids and lipoproteins were measured in the fasting state for cardiovascular risk prediction; however, since 2009 use of nonfasting lipid profiles has increased substantially worldwide. For patients, nonfasting lipid profiles are convenient and avoid any risk of hypoglycemia. For laboratories, blood sampling in the morning and extra visits for patients who have not fasted are avoided. For patients, clinicians, hospitals, and society, nonfasting sampling allows same-day visits with first blood sampling followed by a short wait for test results before clinical consultation. Therefore, nonfasting compared to fasting lipid profiles will save money and time and may improve patient compliance with cardiovascular prevention programs. We report on the progression of endorsement and implementation of nonfasting lipid profiles for cardiovascular risk prediction worldwide and summarize the recommendations from major medical societies and health authorities in different countries. We also describe practical advantages and disadvantages for using nonfasting lipid profiles. Further, we include a description of why fasting has been the standard historically, the barriers against implementation of nonfasting lipid profiles, and finally we suggest the optimal content of a nonfasting lipid profile. Lipid, lipoprotein, and apolipoprotein concentrations vary minimally in response to normal food intake and nonfasting lipid profiles are equal or superior to fasting profiles for cardiovascular risk prediction. Major guidelines and consensus statements in Europe, the United States, Canada, Brazil, Japan, India, and Australia now endorse use of nonfasting lipid profiles in some or all patients; however, there are still gaps in endorsement and implementation of nonfasting lipid profiles worldwide.

Dietary n-3 alpha-linolenic and n-6 linoleic acids modestly lower serum lipoprotein(a) concentration but differentially influence other atherogenic lipoprotein traits: a randomized trial

Background and aimsLipoprotein(a) [Lp(a)] is a causal, genetically determined cardiovascular risk factor. Limited evidence suggests that dietary unsaturated fat may increase serum Lp(a) concentration by 10–15%. Linoleic acid may increase Lp(a) concentration through its endogenous conversion to arachidonic acid, a process regulated by the fatty acid desaturase (FADS) gene cluster. We aimed to compare the Lp(a) and other lipoprotein trait-modulating effects of dietary alpha-linolenic (ALA) and linoleic acids (LA). Additionally, we examined whether FADS1 rs174550 genotype modifies Lp(a) responses. MethodsA genotype-based randomized trial was performed in 118 men homozygous for FADS1 rs174550 SNP (TT or CC). After a 4-week run-in period, the participants were randomized to 8-week intervention diets enriched with either Camelina sativa oil (ALA diet) or sunflower oil (LA diet) 30–50 mL/day based on their BMI. Serum lipid profile was measured at baseline and at the end of the intervention. ResultsALA diet lowered serum Lp(a) concentration by 7.3% (p=0.003) and LA diet by 9.5% (p<0.001) (p=0.089 for between-diet difference). Both diets led to greater absolute decreases in individuals with higher baseline Lp(a) concentration (p<0.001). Concentrations of LDL cholesterol (LDL-C), non-HDL-C, remnant-C, and apolipoprotein B were lowered more by the ALA diet (p<0.01). Lipid or lipoprotein responses were not modified by the FADS1 rs174550 genotype. ConclusionsA considerable increase in either dietary ALA or LA from vegetable oils has a similar Lp(a)-lowering effect, whereas ALA may lower other major atherogenic lipids and lipoproteins to a greater extent than LA. Genetic differences in endogenous PUFA conversion may not influence serum Lp(a) concentration.

Apolipoproteins and the risk of giant cell arteritis—a nested case–control study

BackgroundThe etiology of giant cell arteritis (GCA) and its predictors are incompletely understood. Previous studies have indicated reduced risk of future development of GCA in individuals with obesity and/or diabetes mellitus. There is limited information on blood lipids before the onset of GCA. The objective of the study was to investigate the relation between apolipoprotein levels and future diagnosis of GCA in a nested case–control analysis.MethodsIndividuals who developed GCA after inclusion in a population-based health survey (the Malmö Diet Cancer Study; N = 30,447) were identified by linking the health survey database to the local patient administrative register and the national patient register. A structured review of medical records was performed. Four controls for every validated case, matched for sex, year of birth, and year of screening, were selected from the database. Anthropometric measures, self-reported physical activity, based on a comprehensive, validated questionnaire, and non-fasting blood samples had been obtained at health survey screening. Concentrations of apolipoprotein A-I (ApoA-I) and apolipoprotein B (ApoB) in stored serum were measured using an immunonephelometric assay. Potential predictors of GCA were examined in conditional logistic regression models.ResultsThere were 100 cases with a confirmed clinical diagnosis of GCA (81% female; mean age at diagnosis 73.6 years). The median time from screening to diagnosis was 12 years (range 0.3–19.1). The cases had significantly higher ApoA-I at baseline screening compared to controls (mean 168.7 vs 160.9 mg/dL, odds ratio [OR] 1.57 per standard deviation (SD); 95% confidence interval [CI] 1.18–2.10) (SD 25.5 mg/dL). ApoB levels were similar between cases and controls (mean 109.3 vs 110.4 mg/dL, OR 0.99 per SD; 95% CI 0.74–1.32) (SD 27.1 mg/dL). The ApoB/ApoA1 ratio tended to be lower in cases than in controls, but the difference did not reach significance. The association between ApoA-I and GCA development remained significant in analysis adjusted for body mass index and physical activity (OR 1.48 per SD; 95% CI 1.09–1.99).ConclusionSubsequent development of GCA was associated with significantly higher levels of ApoA-I. These findings suggest that a metabolic profile associated with lower risk of cardiovascular disease may predispose to GCA.

APOE genotype dictates lipidomic signatures in primary human hepatocytes

Apolipoprotein E (APOE) genetic variants are most notably known for their divergent impact on the risk of developing Alzheimer’s disease. While APOE genotype has been consistently shown to modulate lipid metabolism in a variety of cellular contexts, the effect of APOE alleles on the lipidome in hepatocytes is unknown. In this study, we investigated the contribution of APOE alleles to lipidomic profiles of donor-derived primary human hepatocytes from 77 subjects. Lipidomic data obtained by liquid chromatography-mass spectrometry were analyzed across ε2/ε3, ε3/ε3, and ε3/ε4 genotypes to reveal how APOE modulates lipid relative levels over age and between groups. Hepatic APOE concentration, measured by ELISA, was assessed for correlation with lipid abundance in subjects grouped as per APOE genotype and sex. APOE genotype-specific differential lipidomic signatures associated with age for multiple lipid classes but did not differ between sexes. Compared to ε2/ε3, ε3/ε4 hepatocytes had higher abundance of acylcarnitines (AC) and acylphosphatidylglycerol (AcylPG) as a class, as well as higher medium and long-chain ACs, AcylPG, phosphatidylglycerol (PG), bis(monoacylglycerol)phosphate (BMP), monoacylglycerol (MG) and diacylglycerol (DG) species. The ε3/ε4 hepatocytes also exhibited a higher abundance of medium and long-chain ACs compared to the ε3/ε3 hepatocytes. Only in the ε3/ε4 hepatocytes, APOE concentration was lower and showed a negative correlation with BMP levels, specifically in females. APOE genotype dictates a differential lipidome in primary human hepatocytes. The lipids involved suggest mitochondrial dysfunction with accompanying alterations in neutral lipid storage, reflective of a general disturbance of free fatty acid metabolism in human hepatocytes with the ε4 allele.

Role of Apolipoproteins in Neurodegenerative Diseases

Since lipids are insoluble in water, they are carried in the blood as particles called lipoproteins. Lipoproteins consisting of lipids and proteins are multicomponent complexes. The classification of lipoproteins, which are divided into several main groups such as low density lipoprotein (LDL), high density lipoprotein (HDL), very low density lipoprotein (VLDL) and chylomicrons, is based on their density, size, lipid and apolipoprotein content. Apolipoproteins are the protein component of lipoproteins that carry lipids from the blood to various tissues of the body for metabolism and utilisation. Apolipoproteins play an important role in lipid metabolism. They regulate many metabolic enzymes and interact with lipoprotein receptors. Numerous studies have shown that apolipoprotein phenotype, different allelic polymorphism and apolipoprotein gene mutation can affect metabolism and utilisation of blood lipids and consequently trigger the onset and development of atherosclerosis, hyperlipidaemia, cerebrovascular and cardiovascular diseases. Furthermore, apolipoproteins have been associated with neurodegenerative diseases and different apolipoprotein polymorphisms have been evaluated as risk factors or protective agents in different neurodegenerative diseases. This review presents evidence from some studies linking apolipoproteins with Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration disease.

Lipids, lipoproteins, and apolipoproteins during the first year of life: a prospective cohort study

Abstract Background/Introduction Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally, and treatment of well-established lifestyle risk factors are cornerstones in CVD prevention. An atherogenic lipid profile with high concentrations of low-density lipoprotein (LDL) cholesterol and other apolipoprotein B containing lipoproteins is a driving force in the pathogenesis of atherosclerotic CVD (ASCVD). The lifelong atherosclerotic process is proportional to concentrations of apolipoprotein B-containing lipoproteins, hence risk of developing ASCVD is cumulative over time. The higher the baseline concentrations, the sooner the threshold for increased risk of ASCVD will be reached. It is therefore crucial to implement changes as early as possible and prevent risk factors in occurring – so-called primordial prevention. Childhood has been described as a "window of opportunity" for preventing risk factors in occurring and thus avoiding ASCVD. Whether concentrations of atherogenic lipoproteins at birth can predict future concentrations in early childhood and thus may indicate increased risk of dyslipidemia later in life remains unknown. Purpose The aim of the present study was to investigate atherogenic lipid traits during the first year of life, to identify influential factors for lipid concentrations, and to determine whether concentrations at birth can predict future lipid concentrations in early childhood. Methods For this purpose, we used the Copenhagen Baby Heart Study comprising more than 13,000 umbilical cord blood samples and parallel venous blood samples from children and parents at birth (n=444), at two months (n=363), and at 14-16 months (n=158). Lipid traits were determined in all samples. Results Concentrations of low-density lipoprotein (LDL) cholesterol, non-high-density lipoprotein (HDL) cholesterol, and apolipoprotein B increased during the first year of life. Girls had higher concentrations at birth and at two months compared with boys. Children born preterm had higher cord blood concentrations than children born at term. A linear mixed model showed that high concentrations of LDL cholesterol, non-HDL cholesterol and apolipoprotein B at birth predicted high concentrations at two months and at 14-16 months. Multivariable adjusted odds ratios (95% CI) for having high concentrations at two months when children had high concentrations at birth were 1.95 (1.01-3.79) for LDL cholesterol, 1.36 (0.69-2.67) for non-HDL cholesterol and 1.90 (1.02-3.53) for apolipoprotein B. Conclusion The lipid profile change during the first year of life and sex and gestational age influence concentrations. Children with high concentrations of LDL cholesterol, non-HDL cholesterol and apolipoprotein B at birth had higher levels at two and at 14-16 months. Concentrations at birth may thus be used to identify children at risk of dyslipidemia in later life.

Depleting LCAT Aggravates Atherosclerosis in LDLR-deficient Hamster with Reduced LDL-Cholesterol Level

IntroductionLecithin cholesterol acyltransferase (LCAT) plays a crucial role in acyl-esterifying cholesterol in plasma, which is essential for reverse cholesterol transport (RCT). Previous studies indicated that its activity on both α and β lipoproteins interpret its effects on lipoproteins for many controversial investigations of atherosclerosis. ObjectivesTo better understand the relationship between LCAT, diet-induced dyslipidemia and atherosclerosis, we developed a double knockout (LCAT−/−&LDLR−/−, DKO) hamster model to evaluate the specific role of LCAT independent of LDL clearance effects. MethodsPlasma triglyceride (TG), total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), and free cholesterol (FC) levels were measured using biochemical reagent kits. FPLC was performed to analyze the components of lipoproteins. Apolipoprotein content was assessed using western blotting (WB). The hamsters were fed a high cholesterol/high fat diet (HCHFD) to induce atherosclerosis. Oil Red O staining was employed to detect plaque formation. Peritoneal macrophages were studied to investigate the effects of LCAT on cholesterol uptake and efflux. ResultsOn HCHFD, DKO hamsters exhibited significantly elevated levels of TG and FC, while HDL-C was nearly undetectable without affecting TC levels, as compared to low-density lipoprotein receptor (LDLR)-deficient (LDLR−/−, LKO) hamsters. Lipoprotein profiling revealed a marked increase in plasma chylomicron/very low-density lipoprotein (CM/VLDL) fractions, along with an unexpected reduction in LDL fraction in DKO hamsters. Furthermore, DKO hamsters displayed aggravated atherosclerotic lesions in the aorta, aortic root, and coronary artery relative to LKO hamsters, attributed to a pro-atherogenic lipoprotein profile and impaired cholesterol efflux in macrophages. ConclusionsOur study demonstrates the beneficial role of LCAT in inhibiting atherosclerotic development and highlights the distinctive lipid metabolism characteristics in hamsters with familial hypercholesterolemia.

Significance of lipids, lipoproteins, and apolipoproteins during the first 14-16 months of life.

The aims of this study were to investigate lipid parameters during the first 14-16 months of life, to identify influential factors, and to test whether high concentrations at birth predict high concentrations at 2- and 14-16 months. The Copenhagen Baby Heart Study, including 13,354 umbilical cord blood samples and parallel venous blood samples from children and parents at birth (n = 444), 2 months (n = 364), and 14-16 months (n = 168), was used. Concentrations of lipids, lipoproteins, and apolipoproteins in umbilical cord blood samples correlated highly with venous blood samples from newborns. Concentrations of low-density lipoprotein (LDL) cholesterol, non-high-density lipoprotein (HDL) cholesterol, apolipoprotein B, and lipoprotein(a) increased stepwise from birth to 2 months to 14-16 months. Linear mixed models showed that concentrations of LDL cholesterol, non-HDL cholesterol, and lipoprotein(a) above the 80th percentile at birth were associated with significantly higher concentrations at 2 and 14-16 months. Finally, lipid concentrations differed according to sex, gestational age, birth weight, breastfeeding, and parental lipid concentrations. Lipid parameters changed during the first 14-16 months of life, and sex, gestational age, birth weight, breastfeeding, and high parental concentrations influenced concentrations. Children with high concentrations of atherogenic lipid traits at birth had higher concentrations at 2 and 14-16 months. These findings increase our knowledge of how lipid traits develop over the first 14-16 months of life and may help in deciding the optimal child age for universal familial hypercholesterolaemia screening.

449-P: Truncations of Apolipoproteins C-I and C-II Are Associated with Coronary Artery Calcium Progression in Multiethnic Study of Atherosclerosis (MESA)

Higher truncated-to-native proteoform ratios of apolipoproteins (apo) C-I (C-I’/C-I) and C-II (C-II’/C-II) are associated with less atherogenic lipid profiles, including lower triglycerides (TG) and higher HDL levels. Here we examined the relationships of C-I’/C-II and C-II’/C-II, and total apoC-I and apoC-II concentrations with coronary artery calcium (CAC) progression. Apo C-I and C-II proteoforms were measured by mass spectrometry immunoassay in 5,791 baseline MESA plasma samples. Total apo C-I and C-II concentrations were assayed in 3,851 samples. CAC was measured 1 to 4 times (mean 2.5) over 10 years. Repeated measures regression models were adjusted for age, gender, race/ethnicity, and follow-up time (Model 1), then for BMI, diabetes, systolic BP, use of tobacco, statins and antihypertensive medications (Model 2), and then for plasma HDL and TG (Model 3). Among 5,069 participants with at least one follow-up CAC CT scan, 2,513 had CAC progression defined as events of CAC changing from 0 to &amp;gt; 0, or ≥ 10 units/yr from CAC &amp;gt; 0 but ≤ 100, or ≥ 10%/yr from CAC &amp;gt; 100. Progression was inversely associated with C-I’/C-I (Risk Ratio per 1 SD: 0.93 [95% CI 0.87, 0.97], Model 3). In those with baseline CAC = 0 (n = 2,581), risk of CAC &amp;gt; 0 (897 events) was inversely associated with C-I’/C-I in Model 1 only (0.85 [0.79, 0.93]). In those with baseline CAC &amp;gt; 0, C-II’/C-II was positively associated with follow-up change in density score (β-estimate per 1 SD 0.02 [95% CI: 0.001, 0.03] units) in Model 3, indicating a potentially more stable plaque. Baseline-adjusted follow-up density score was also positively related to total apoC-I in Model 2 (0.02 [0.004, 0.04]). None of the CAC measures were related to total apoC-II. In conclusion, increased truncation of apo C-I and C-II is associated with reduced CAC progression and/or improved stability of coronary atherosclerotic plaque that is not explained by total concentrations of both apolipoproteins. Disclosure J.Koska: None. J.Furtado: Employee; Biogen. Y.Hu: None. D.Billheimer: Advisory Panel; AstraZeneca. M.Allison: None. M.Budoff: Research Support; Novo Nordisk, Novartis, Boehringer Ingelheim Inc., Speaker's Bureau; Boehringer Ingelheim and Eli Lilly Alliance. D.Nedelkov: None. R.Mcclelland: None. P.Reaven: Research Support; Dexcom, Inc. Funding National Heart, Lung, and Blood Institute (R01HL138969, 75N92020D00001, HHSN268201500003I, N01HC95159, 75N92020D00005, N01HC95160, 75N92020D00002, N01HC95161, 75N92020D00003, N01HC95162, 75N92020D00006, N01HC95163, 75N92020D00004, N01HC95164, 75N92020D000

Characterization of lipoproteins in human placenta and fetal circulation as well as gestational changes in lipoprotein assembly and secretion in human and mouse placentas

In the maternal circulation, apoB-containing low-density lipoproteins (LDL) and apoA1-containing high-density lipoproteins (HDL) transport lipids. The production of lipoproteins in the placenta has been suggested, but the directionality of release has not been resolved. We compared apolipoprotein concentrations and size-exclusion chromatography elution profiles of lipoproteins in maternal/fetal circulations, and in umbilical arteries/veins; identified placental lipoprotein-producing cells; and studied temporal induction of lipoprotein-synthesizing machinery during pregnancy. We observed that maternal and fetal lipoproteins are different with respect to concentrations and elution profiles. Surprisingly, concentrations and elution profiles of lipoproteins in umbilical arteries and veins were similar indicating their homeostatic control. Human placental cultures synthesized apoB100-containing LDL-sized and apoA1-containing HDL-sized particles. Immunolocalization techniques revealed that ApoA1 was present mainly in syncytiotrophoblasts. MTP, a critical protein for lipoprotein assembly, was in these trophoblasts. ApoB was in the placental stroma indicating that trophoblasts secrete apoB-containing lipoproteins into the stroma. ApoB and MTP expressions increased in placentas from the 2nd trimester to term, whereas apoA1 expression was unchanged. Thus, our studies provide new information regarding the timing of lipoprotein gene induction during gestation, the cells involved in lipoprotein assembly and the gel filtration profiles of human placental lipoproteins.Next, we observed that mouse placenta produces MTP, apoB100, apoB48 and apoA1. The expression of genes gradually increased and peaked in late gestation. This information may be useful in identifying transcription factors regulating the induction of these genes in gestation and the importance of placental lipoprotein assembly in fetal development.

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.

Metrologically Traceable Quantification of 3 Apolipoprotein E Isoforms in Cerebrospinal Fluid.

APOE genotype is associated with Alzheimer disease. Thus, the concentration of apolipoprotein E (apoE) isoforms in cerebrospinal fluid (CSF) could be altered in dementia. However, conflicting results have been obtained in different studies. Carefully validated and standardized assays could improve the interpretation of research findings, allow their replication in other laboratories, and generalize their application. To evaluate this hypothesis, we aimed to develop, validate, and standardize a new measurement procedure using LC-MS/MS. Purified recombinant apoE protein standards (E2, E3, E4) were thoroughly characterized and used to assign the concentration of a matrix-matched calibration material that contained each apoE isoform, which ensured the metrological traceability of results. The assay of each isoform in human CSF was precise (≤11%CV) and of moderate throughput (approximately 80 samples per day). It demonstrated good linearity and parallelism for lumbar CSF, ventricular CSF, and bovine CSF. The use of an SI-traceable matrix-matched calibrator enabled precise and accurate measurements. There was no association observed between total apoE concentration and the number of Ɛ4 alleles in a cohort of 322 participants. However, the concentration of each isoform was significantly different in heterozygotes, with E4 > E3 > E2. Isoform concentrations were associated with cognitive and motor symptoms but contributed negligibly to a predictive model of cognitive impairment that included established CSF biomarkers. Our method simultaneously measures each apoE isoform in human CSF with excellent precision and accuracy. A secondary matrix-matched material has been developed and is available to other laboratories to improve interlaboratory agreement.

Obicetrapib plus ezetimibe as an adjunct to high-intensity statin therapy: A randomized phase 2 trial

Obicetrapib, a selective cholesteryl ester transfer protein (CETP) inhibitor, reduces low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), lipoprotein particles, and apolipoproteins, when added to high-intensity statin in patients with dyslipidemia. To evaluate the safety and lipid-altering efficacy of obicetrapib plus ezetimibe combination therapy as an adjunct to high-intensity statin therapy. This double-blind, randomized, phase 2 trial administered 10mg obicetrapib plus 10mg ezetimibe (n=40), 10mg obicetrapib (n=39), or placebo (n=40) for 12 weeks to patients with LDL-C >70mg/dL and triglycerides (TG) <400mg/dL, on stable high-intensity statin. Endpoints included concentrations of lipids, apolipoproteins, lipoprotein particles, and proprotein convertase subtilisin kexin type 9 (PCSK9), safety, and tolerability. Ninety-seven patients were included in the primary analysis (mean age 62.6 years, 63.9% male, 84.5% white, average body mass index of 30.9kg/m2). LDL-C decreased from baseline to week 12 by 63.4%, 43.5%, and 6.35% in combination, monotherapy, and placebo groups, respectively (p<0.0001vs. placebo). LDL-C levels of <100, <70, and <55mg/dL were achieved by 100%, 93.5%, and 87.1%, respectively, of patients taking the combination. Both active treatments also significantly reduced concentrations of non-HDL-C, apolipoprotein B, and total and small LDL particles. Obicetrapib was well tolerated and no safety issues were identified. The combination of obicetrapib plus ezetimibe significantly lowered atherogenic lipid and lipoprotein parameters, and was safe and well tolerated when administered on top of high-intensity statin to patients with elevated LDL-C.

Associations of perfluoroalkyl substances (PFAS) with lipid and lipoprotein profiles

BackgroundPerfluoroalkyl substances (PFAS) are man-made chemicals with unique properties that are widely distributed in humans and the environment. Recent studies suggest that PFAS are involved in cholesterol metabolism, however, the mechanisms underlying the associations are poorly understood.ObjectiveWe aimed to evaluate associations of plasma PFAS with detailed lipid and lipoprotein subfractions in an adult population of men and women.MethodsWe measured concentrations of cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein subclasses, as well as fatty acid and different phospholipid measures, using serum proton nuclear magnetic resonance (1H-NMR), and four plasma PFAS using liquid chromatography-mass spectrometry (UHPLC-MS/MS). Measurements were available for 493 participants (all aged 50 years, 50% female). Multivariable linear regression was used to estimate the association of four PFAS with 43 different 1H-NMR measures, with adjustment for body mass index (BMI), smoking, education, and physical activity.ResultsWe found that perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), but not perfluorohexanesulfonate (PFHxS), concentrations were consistently positively associated with concentrations of cholesterol in lipoprotein subfractions, apolipoproteins, as well as composite fatty acid- and phospholipid profiles. The most consistent associations were found for the relationship of PFAS with total cholesterol in intermediate-density lipoprotein (IDL), across all low-density lipoprotein (LDL) subfractions and small high-density lipoprotein (HDL). Moreover, we found weak to null evidence for an association of any of the measured 13 triglyceride lipoprotein subfractions with PFAS.ConclusionsOur results suggest that plasma PFAS concentrations are associated with cholesterol in small HDL, IDL and all LDL subfractions, as well as apolipoproteins and composite fatty acid and phospholipid profiles but to a lesser extent with triglycerides in lipoproteins. Our findings draw attention to the need for more detailed measurements of lipids across various lipoprotein subfractions and subclasses in assessing the role of PFAS in lipid metabolism.ImpactBy performing an in-depth characterization of circulating cholesterol and triglycerides in lipoprotein subfractions, apolipoprotein, fatty acid, and phospholipid concentrations, this study has expanded upon the limited literature available on the associations of plasma PFAS concentrations beyond clinical routine laboratory testing for lipids.

Dietary Monounsaturated and Polyunsaturated Fatty Acids are Comparable in their Effects on Hepatic Apolipoprotein mRNA Abundance and Liver Lipid Concentrations when Substituted for Saturated Fatty Acids in Cynomolgus Monkeys

Although studies have shown that saturated and polyunsaturated fats can mediate plasma lipid and apolipoprotein (apo) concentrations at the mRNA level, there is little data on the role of monounsaturated fats. We determined hepatic lipid and apo mRNA levels in 10 cynomolgus monkeys fed three diets that provided 30% of energy as fat with 0.1% cholesterol by weight and differed solely by the substitution of saturated, mono- and polyunsaturated fats as 60% of total fat energy. Total, LDL, and HDL cholesterol, as well as LDL apo B, HDL apo A-I and HDL total apo C concentrations, were reduced with the mono- and polyunsaturated fat diets relative to the saturated fat diet. Although fat saturation did not significantly affect hepatic apo A-I, B, C-II, or E mRNA abundance, hepatic apo C-III mRNA concentrations were uniformly lower (-23%, P < 0.01) with the mono- and polyunsaturated fat diets than with the saturated fat diet. Interestingly, liver triglycerides were significantly elevated with the monounsaturated fat diet relative to the saturated fat diet, but no other differences in hepatic lipids were noted among diets. Hepatic triglyceride composition was shown to reflect dietary fatty acid composition, with liver triglycerides enriched in myristic and palmitic fatty acids during the saturated fat diet, oleic acid during the monounsaturated fat diet and linoleic acid during the polyunsaturated fat diet. We conclude that dietary monounsaturated fats are comparable to polyunsaturated fats in their effects on hepatic lipid and apo mRNA levels in this species, with both unsaturated fats significantly reducing only hepatic apo C-III mRNA abundance relative to saturated fat.

Sphingolipidomic profile and HDL subfractions in obese dyslipidemic type 2 diabetic patients

PurposeThe aim of the study was to investigate changes in serum sphingolipid levels and high density lipoprotein (HDL) subtypes with relation to low-density lipoprotein cholesterol (LDL-C), non-HDL-C and triglyceride (TG) levels in type 2 diabetes mellitus (T2DM) patients. MethodsBlood was obtained from 60 patients with T2DM. Levels of sphingosine-1-phosphate (S1P), C16-C24 sphingomyelins (SMs), C16-C24 ceramides (CERs), and C16 CER-1 P were determined by LC-MS/MS. Serum concentrations of cholesterol ester transfer protein (CETP), lecithin-cholesterol acyltransferase (LCAT) and apolipoprotein A-1 (apoA-I) were analyzed by enzyme-linked immunosorbent assay (ELISA). HDL subfraction analysis was performed by Disc polyacrylamide gel electrophoresis. ResultsC16 SM, C24 SM, C24-C16 CER and C16 CER-1 P levels were significantly increased in T2DM patients with LDL-C above 160 mg/dL, compared to those with LDL-C below 100 mg/dL. A significant correlation was observed between C24:C16 SM, C24:C16 CER ratios and LDL-C, non HDL-C levels. Higher serum levels of C24 SM, C24-C18 CER and C24:C16 SM ratio was seen in obese T2DM patients (BMI>30) compared to those with BMI 27–30. Patients with fasting TG levels below 150 mg/dL had significantly increased HDL-large and significantly decreased HDL-small fractions compared to those with fasting TG levels above 150 mg/dL. ConclusionObese dyslipidemic T2DM patients had increased levels of serum sphingomyelins, ceramides and HDL-small fractions. The ratio of serum C24:C16 SM, C24:C16 CER and long chain CER levels may be used as diagnostic and prognostic indicators of dyslipidemia in T2DM.

Abstract 18: Impact of Preeclampsia on Cardiovascular Risk Factors in Mothers and Newborns

Introduction: Preeclampsia is a multifactorial disease and a cause of maternal and neonatal morbidity and mortality. Women with preeclampsia have increased risk of cardiovascular diseases in later life. The impact on the offspring is, however, still uncertain. Lipid traits in newborns are considered to reflect the child’s own production. Hypothesis: We assessed the hypothesis that preeclampsia increases risk of future cardiovascular disease in both mother and offspring. Methods: For this purpose, we used the Copenhagen General Population Study comprising 59,571 women of which 1,365 had a diagnosis of preeclampsia to investigate the association between preeclampsia and risk of cardiovascular diseases. Further, we used the Copenhagen Baby Heart Study comprising more than 13,000 umbilical cord blood samples and assessed the impact of preeclampsia on atherogenic lipid traits in cord blood. Results: Age adjusted hazard ratios for preeclampsia versus no preeclampsia (95% CI) were 1.48 (1.13-1.94) for ischemic heart disease, 1.50 (1.07-2.12) for ischemic cerebrovascular disease, and 1.53 (1.22-1.91) for composite vascular disease. Corresponding multivariable adjusted hazard ratios (95% CI) were 1.31 (1.00-1.72), 1.44 (1.02-2.02), and 1.39 (1.11-1.74). Concentrations of non-HDL cholesterol, total cholesterol, LDL cholesterol, apolipoprotein B, and triglycerides in cord blood increased stepwise from no preeclampsia (n=11,221) to mild/moderate preeclampsia (n=253) to severe preeclampsia (n=104) (p for trends &lt;0.0001 for non-HDL cholesterol, total cholesterol and LDL cholesterol; p for trend=0.0002 for apolipoprotein B; p for trend=0.003 for triglycerides). Multivariable adjusted odds ratios (95% CI) for preeclampsia versus no preeclampsia (reference) for cord blood concentrations above the 80 th percentile were 2.09 (1.67-2.61) for non-HDL cholesterol, 1.58 (1.25-2.01) for total cholesterol, 1.72 (1.37-2.16) for LDL cholesterol, 1.38 (1.07-1.78) for apolipoprotein B, and 2.64 (2.07-3.35) for triglycerides. Conclusion: Women with preeclampsia had increased risk of future cardiovascular disease and lipid traits in umbilical cord blood of their offspring were elevated. This indicates that preeclampsia affects lipid metabolism during fetal life and potentially contributes to an increased risk of future cardiovascular disease in offspring of mothers with preeclampsia.

Hypercholesterolemia Induced by Cholesterol- or Cystine-Enriched Diets is Characterized by Different Plasma Lipoprotein and Apolipoprotein Concentrations in Rats

This study examined the effects of diet-induced hypercholesterolemia on plasma apolipoprotein (apo) concentrations and hepatic apolipoprotein mRNA levels in rats. Hypercholesterolemia was induced by feeding rats diets containing an excess of either cholesterol or cystine. After cholesterol feeding, plasma apo E and apo B concentrations were lower (-65%, P < 0.001) and greater (+39%, P < 0.01), respectively, compared with control diet-fed rats. After cystine feeding, plasma apo B and apo E concentrations were greater (+46%, P < 0.01 and +75%, P < 0.001, respectively) and plasma apo A-IV concentration was lower (-29%, P < 0.001) than in rats fed control diet. After cholesterol or cystine feeding, a tendency (one-way ANOVA, P = 0.08) for greater apo B mRNA level (+42% and +47%, respectively) was observed compared with control diet-fed rats. No difference emerged between groups for apo E and apo A-I mRNA levels. An opposite effect of cholesterol and cystine feeding was shown for apo A-IV mRNA level, i.e., higher after cholesterol feeding (+47%, P < 0.05) and lower after cystine feeding (-65%, P < 0.01). From this work, it seems that hypercholesterolemia induced by dietary cholesterol or by increased cholesterogenesis in cystine-fed rats is characterized by different plasma lipoprotein and apolipoprotein concentrations and is associated with different apolipoprotein gene expression in the liver.

Plasma Apolipoprotein Concentrations Are Highly Altered in Severe Intensive Care Unit COVID-19 Patients: Preliminary Results from the LIPICOR Cohort Study.

SARS-CoV-2 infection goes beyond acute pneumonia, as it also impacts lipid metabolism. Decreased HDL-C and LDL-C levels have been reported in patients with COVID-19. The lipid profile is a less robust biochemical marker than apolipoproteins, components of lipoproteins. However, the association of apolipoprotein levels during COVID-19 is not well described and understood. The objective of our study is to measure plasma levels of 14 apolipoproteins in patients with COVID-19 and to evaluate the relationships between apolipoprotein levels, severity factors and patient outcomes. From November to March 2021, 44 patients were recruited on admission to the intensive care unit because of COVID-19. Fourteen apolipoproteins and LCAT were measured by LC-MS/MS in plasma of 44 COVID-19 patients on admission to the ICU and 44 healthy control subjects. Absolute apolipoprotein concentrations were compared between COVID-19 patients and controls. Plasma apolipoproteins (Apo) A (I, II, IV), C(I, II), D, H, J and M and LCAT were lower in COVID-19 patients, whereas Apo E was higher. COVID-19 severity factors such as PaO2/FiO2 ratio, SO-FA score and CRP were correlated with certain apolipoproteins. Lower Apo B100 and LCAT levels were observed in non-survivors of COVID-19 versus survivors. To conclude, in this study, lipid and apolipoprotein profiles are altered in COVID-19 patients. Low Apo B100 and LCAT levels may be predictive of non-survival in COVID-19 patients.

Apolipoprotein mRNA in Liver and Intestine of Rats is Affected by Dietary Beet Fiber or Cholestyramine

Rats were fed a cholesterol-free diet with no added fiber (fiber-free) or with 15 g/100 g beet fiber or 5 g/100 g cholestyramine for 14 d. Final plasma total cholesterol concentrations were significantly lower in rats fed beet fiber than in those fed fiber-free or cholestyramine diets. This difference was due mainly to lower HDL cholesterol concentrations. The group fed beet fiber also tended (P < 0.1) to have lower apolipoprotein A-I concentration in plasma. Northern blot analysis revealed that the relative concentrations of jejunal apolipoprotein A-I and A-IV mRNA were the same in all groups, whereas ileal apolipoprotein A-I and A-IV mRNA levels were significantly lower in rats fed beet fiber or cholestyramine than in those fed the fiber-free diet. Hepatic apolipoprotein E mRNA concentrations were the same in all groups, but apolipoprotein A-I mRNA levels were significantly lower in rats fed beet fiber than in those fed the other diets. Apolipoprotein A-IV mRNA tended (P < 0.1) to be lower in rats fed the beet fiber diet. These data suggest that the hypocholesterolemic effect of dietary beet fiber is associated with diminished expression of the hepatic apolipoprotein A-I gene.