JLR Patient-Oriented and Epidemiological Research
Depletion in LpA-I:A-II particles enhances HDL-mediated endothelial protection in familial LCAT deficiency
The aim of this study was to evaluate the vasoprotective effects of HDL isolated from carriers of LCAT deficiency, which are characterized by a selective depletion of LpA-I:A-II particles and predominance of preβ migrating HDL. HDLs were isolated from LCAT-deficient carriers and tested in vitro for their capacity to promote NO production and to inhibit vascular cell adhesion molecule-1 (VCAM-1) expression in cultured endothelial cells. HDLs from carriers were more effective than control HDLs in promoting eNOS activation with a gene-dose-dependent effect (PTrend = 0.048).A newborn screening method for cerebrotendinous xanthomatosis using bile alcohol glucuronides and metabolite ratios
Cerebrotendinous xanthomatosis (CTX) is a treatable neurodegenerative metabolic disorder of bile acid synthesis in which symptoms can be prevented if treatment with chenodeoxycholic acid supplementation is initiated early in life, making CTX an excellent candidate for newborn screening. We developed a new dried blood spot (DBS) screening assay for this disorder on the basis of different ratios between the accumulating cholestanetetrol glucuronide (tetrol) and specific bile acids/bile acid intermediates, without the need for derivatization.Analysis of glycero-lysophospholipids in gastric cancerous ascites
Lysophosphatidic acid (LysoPA) has been proposed to be involved in the pathogenesis of various cancers. Moreover, glycero-lysophospholipids (glycero-LysoPLs) other than LysoPA are now emerging as novel lipid mediators. Therefore, we aimed to elucidate the possible involvement of glycero-LysoPLs in the pathogenesis of gastric cancer by measuring glycero-LysoPLs, autotaxin (ATX), and phosphatidylserine-specific phospholipase A1 (PS-PLA1) in ascites obtained from patients with gastric cancer and those with cirrhosis (as a control).Unsupervised analysis of combined lipid and coagulation data reveals coagulopathy subtypes among dialysis patients
Hemodialysis (HD) and peritoneal dialysis (PD) are the primary means of managing end stage renal disease (ESRD). However, these treatment modalities are associated with the onset of coagulation abnormalities. Effective management of coagulation risk among these patients requires the identification of surrogate markers that provide an early indication of the coagulation abnormalities. The role of sphingolipids in the manifestation and prediction of coagulation abnormalities among dialysis patients have never been investigated.HDL efflux capacity, HDL particle size, and high-risk carotid atherosclerosis in a cohort of asymptomatic older adults: the Chicago Healthy Aging Study
HDL efflux capacity and HDL particle size are associated with atherosclerotic CVD (ASCVD) events in middle-aged individuals; however, it is unclear whether these associations are present in older adults. We sampled 402 Chicago Healthy Aging Study participants who underwent a dedicated carotid MRI assessment for lipid-rich necrotic core (LRNC) plaque. We measured HDL particle size, HDL particle number, and LDL particle number with NMR spectroscopy, as well as HDL efflux capacity. We quantified the associations between HDL particle size and HDL efflux using adjusted linear regression models.Prognostic roles of tetrahydroxy bile acids in infantile intrahepatic cholestasis
Tetrahydroxy bile acids (THBAs) are hydrophilic and are present at minimal or undetectable levels in healthy human adults, but are present at high levels in bile salt export pump (abcb11)-knockout mice. The roles of THBAs in human cholestatic diseases are unclear. We aimed to investigate the presence of THBAs in patients with infantile intrahepatic cholestasis and its correlation with outcome. Urinary bile acids (BAs) were analyzed by GC-MS. Data were compared between good (n = 21) (disease-free before 1 year old) and poor prognosis groups (n = 19).Different origins of lysophospholipid mediators between coronary and peripheral arteries in acute coronary syndrome
Lysophosphatidic acids (LysoPAs) and lysophosphatidylserine (LysoPS) are emerging lipid mediators proposed to be involved in the pathogenesis of acute coronary syndrome (ACS). In this study, we attempted to elucidate how LysoPA and LysoPS become elevated in ACS using human blood samples collected simultaneously from culprit coronary arteries and peripheral arteries in ACS subjects. We found that: 1) the plasma LysoPA, LysoPS, and lysophosphatidylglycerol levels were not different, while the lysophosphatidylcholine (LysoPC), lysophosphatidylinositol, and lysophosphatidylethanolamine (LysoPE) levels were significantly lower in the culprit coronary arteries; 2) the serum autotaxin (ATX) level was lower and the serum phosphatidylserine-specific phospholipase A1 (PS-PLA1) level was higher in the culprit coronary arteries; 3) the LysoPE and ATX levels were significant explanatory factors for the mainly elevated species of LysoPA, except for 22:6 LysoPA, in the peripheral arteries, while the LysoPC and LysoPE levels, but not the ATX level, were explanatory factors in the culprit coronary arteries; and 4) 18:0 and 18:1 LysoPS were significantly correlated with PS-PLA1 only in the culprit coronary arteries.The influence of placental metabolism on fatty acid transfer to the fetus
The factors determining fatty acid transfer across the placenta are not fully understood. This study used a combined experimental and computational modeling approach to explore placental transfer of nonesterified fatty acids and identify the rate-determining processes. Isolated perfused human placenta was used to study the uptake and transfer of 13C-fatty acids and the release of endogenous fatty acids. Only 6.2 ± 0.8% of the maternal 13C-fatty acids taken up by the placenta was delivered to the fetal circulation.On the importance of albumin binding for the flux of 7α-hydroxy-3-oxo-4-cholestenoic acid in the brain
We confirmed previous findings by a Japanese group that there is an accumulation of 7α-hydroxy-3-oxo-4-cholestenoic acid (7-Hoca) in human subdural hematomas. The accumulation correlated with the time from the bleeding to the sample collection. We present evidence that these accumulations are likely to be caused by the strong affinity of 7-Hoca to albumin and the marked difference between plasma and brain with respect to levels of albumin. In the circulation, 80–90% of 7-Hoca is bound to albumin with a ratio between the steroid acid and albumin of ∼1.4 ng/mg.Combined effects of the PNPLA3 rs738409, TM6SF2 rs58542926, and MBOAT7 rs641738 variants on NAFLD severity: a multicenter biopsy-based study
The PNPLA3 p.I148M, TM6SF2 p.E167K, and MBOAT7 rs641738 variants represent genetic risk factors for nonalcoholic fatty liver disease (NAFLD). Here we investigate if these polymorphisms modulate both steatosis and fibrosis in patients with NAFLD. We recruited 515 patients with NAFLD (age 16–88 years, 280 female patients). Liver biopsies were performed in 320 patients. PCR-based assays were used to genotype the PNPLA3, TM6SF2, and MBOAT7 variants. Carriers of the PNPLA3 and TM6SF2 risk alleles showed increased serum aspartate aminotransferase and alanine transaminase activities (P < 0.05).Association of peripheral differential leukocyte counts with dyslipidemia risk in Chinese patients with hypertension: insight from the China Stroke Primary Prevention Trial
The aim of the present study was to examine the association between peripheral differential leukocyte counts and dyslipidemia in a Chinese hypertensive population. A total of 10,866 patients with hypertension were enrolled for a comprehensive assessment of cardiovascular risk factors using data from the China Stroke Primary Prevention Trial. Plasma lipid levels and total leukocyte, neutrophil, and lymphocyte counts were determined according to standard methods. Peripheral differential leukocyte counts were consistently and positively associated with serum total cholesterol (TC), LDL cholesterol (LDL-C), and TG levels (all P < 0.001 for trend), while inversely associated with HDL cholesterol levels (P < 0.05 for trend).Defective cholesterol metabolism in amyotrophic lateral sclerosis
As neurons die, cholesterol is released in the central nervous system (CNS); hence, this sterol and its metabolites may represent a biomarker of neurodegeneration, including in amyotrophic lateral sclerosis (ALS), in which altered cholesterol levels have been linked to prognosis. More than 40 different sterols were quantified in serum and cerebrospinal fluid (CSF) from ALS patients and healthy controls. In CSF, the concentration of cholesterol was found to be elevated in ALS samples. When CSF metabolite levels were normalized to cholesterol, the cholesterol metabolite 3β,7α-dihydroxycholest-5-en-26-oic acid, along with its precursor 3β-hydroxycholest-5-en-26-oic acid and product 7α-hydroxy-3-oxocholest-4-en-26-oic acid, were reduced in concentration, whereas metabolites known to be imported from the circulation into the CNS were not found to differ in concentration between groups.Epigenome-wide association study of triglyceride postprandial responses to a high-fat dietary challenge
Postprandial lipemia (PPL), the increased plasma TG concentration after consuming a high-fat meal, is an independent risk factor for CVD. Individual responses to a meal high in fat vary greatly, depending on genetic and lifestyle factors. However, only a few loci have been associated with TG-PPL response. Heritable epigenomic changes may be significant contributors to the unexplained inter-individual PPL variability. We conducted an epigenome-wide association study on 979 subjects with DNA methylation measured from CD4+ T cells, who were challenged with a high-fat meal as a part of the Genetics of Lipid Lowering Drugs and Diet Network study.Higher chylomicron remnants and LDL particle numbers associate with CD36 SNPs and DNA methylation sites that reduce CD36
Cluster of differentiation 36 (CD36) variants influence fasting lipids and risk of metabolic syndrome, but their impact on postprandial lipids, an independent risk factor for cardiovascular disease, is unclear. We determined the effects of SNPs within a ∼410 kb region encompassing CD36 and its proximal and distal promoters on chylomicron (CM) remnants and LDL particles at fasting and at 3.5 and 6 h following a high-fat meal (Genetics of Lipid Lowering Drugs and Diet Network study, n = 1,117). Five promoter variants associated with CMs, four with delayed TG clearance and five with LDL particle number.Associations of genetic variants for adult lipid levels with lipid levels in children. The Generation R Study
Lipid concentrations are heritable traits. Recently, the number of known genetic loci associated with lipid levels in adults increased from 95 to 157. The effects of these 157 loci have not been tested in children. Considering that lipid levels track from childhood to adulthood, we studied to determine whether these variants already affected lipid concentrations in a large group of 2,645 children with a median age of 6.0 years (95% range 5.7–7.3 years) from the population-based Generation R Study.Increasing insulin resistance accentuates the effect of triglyceride-associated loci on serum triglycerides during 5 years
Blood concentrations of triglycerides are influenced by genetic factors as well as a number of environmental factors, including adiposity and glucose homeostasis. The aim was to investigate the association between a serum triglyceride weighted genetic risk score (wGRS) and changes in fasting serum triglyceride level over 5 years and to test whether the effect of the wGRS was modified by 5 year changes of adiposity, insulin resistance, and lifestyle factors. A total of 3,474 nondiabetic individuals from the Danish Inter99 cohort participated in both the baseline and 5 year follow-up physical examinations and had information on the wGRS comprising 39 genetic variants.Monoacylglycerol-enriched oil increases EPA/DHA delivery to circulatory system in humans with induced lipid malabsorption conditions
It was hypothesized that under induced lipid malabsorption/maldigestion conditions, an enriched sn-1(3)-monoacylglycerol (MAG) oil may be a better carrier for n-3 long-chain PUFAs (LC-PUFAs) compared with triacylglycerol (TAG) from fish oil. This monocentric double blinded clinical trial examined the accretion of EPA (500 mg/day) and DHA (300 mg/day) when consumed as TAG or MAG, into the erythrocytes, plasma, and chylomicrons of 45 obese (BMI ≥30 kg/m2 and ≤40 kg/m2) volunteers who were and were not administered Orlistat, an inhibitor of pancreatic lipases.Effect of evolocumab on cholesterol synthesis and absorption
The effects of cholesterol-lowering drugs, including those that reduce cholesterol synthesis (statins) and those that reduce cholesterol absorption (ezetimibe), on cholesterol absorption and synthesis are well understood. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are a novel class of cholesterol-lowering drugs that robustly reduce LDL-cholesterol (LDL-C), but little is known about their effects on cholesterol absorption and synthesis. We evaluated how treatment with evolocumab, a fully human monoclonal IgG2 antibody to PCSK9, affects markers of cholesterol synthesis and absorption by measuring these markers in patients from an evolocumab clinical trial.The relationship between non-HDL cholesterol and macrophage phenotypes in human adipose tissue
Data from experimental animal models and in vitro studies suggest that both hyperlipoproteinemia and obesity predispose to development of proinflammatory pathways of macrophages within adipose tissue. The aim of this study was to analyze whether non-HDL cholesterol concentration in healthy living kidney donors (LKDs) is related to the number and phenotype of proinflammatory macrophages in visceral and subcutaneous adipose tissue. Adipose tissue samples were collected by cleansing the kidney grafts of LKDs obtained peroperatively.Clinical chorioamnionitis at term: the amniotic fluid fatty acyl lipidome
Clinical chorioamnionitis at term (TCC) is the most common obstetrical infliction diagnosed in labor and delivery units worldwide and is associated with a substantial increase in maternal and neonatal morbidity and mortality. This obstetrical complication is a heterogeneous condition, as only half of patients have detectable microorganisms in the amniotic cavity. Because bioactive lipids play a key role in the initiation and resolution of an inflammatory response, we aimed to characterize the amniotic fluid lipidome in patients with TCC.Differential effects of EPA versus DHA on postprandial vascular function and the plasma oxylipin profile in men
Our objective was to investigate the impact of EPA versus DHA on arterial stiffness and reactivity and underlying mechanisms (with a focus on plasma oxylipins) in the postprandial state. In a three-arm crossover acute test meal trial, men (n = 26, 35–55 years) at increased CVD risk received a high-fat (42.4 g) test meal providing 4.16 g of EPA or DHA or control oil in random order. At 0 h and 4 h, blood samples were collected to quantify plasma fatty acids, long chain n-3 PUFA-derived oxylipins, nitrite and hydrogen sulfide, and serum lipids and glucose.Statin action enriches HDL3 in polyunsaturated phospholipids and plasmalogens and reduces LDL-derived phospholipid hydroperoxides in atherogenic mixed dyslipidemia
Atherogenic mixed dyslipidemia associates with oxidative stress and defective HDL antioxidative function in metabolic syndrome (MetS). The impact of statin treatment on the capacity of HDL to inactivate LDL-derived, redox-active phospholipid hydroperoxides (PCOOHs) in MetS is indeterminate. Insulin-resistant, hypertriglyceridemic, hypertensive, obese males were treated with pitavastatin (4 mg/day) for 180 days, resulting in marked reduction in plasma TGs (−41%) and LDL-cholesterol (−38%), with minor effects on HDL-cholesterol and apoAI.Plasma fatty acids, oxylipins, and risk of myocardial infarction: the Singapore Chinese Health Study
We aimed to examine the prospective association between plasma FAs, oxylipins, and risk of acute myocardial infarction (AMI) in a Singapore Chinese population. A nested case-control study with 744 incident AMI cases and 744 matched controls aged 47–83 years was conducted within the Singapore Chinese Health Study. Nineteen plasma FAs and 12 oxylipins were quantified using MS. These were grouped into 12 FA clusters and 5 oxylipin clusters using hierarchical clustering, and their associations with AMI risk were assessed.ApoL1 levels in high density lipoprotein and cardiovascular event presentation in patients with familial hypercholesterolemia
HDL composition rather than HDL-cholesterol (HDL-C) levels seems to be a key determinant of HDL-induced atheroprotection. Heterozygous familial hypercholesterolemia (FH) patients, with lifelong exposure to high LDL levels, show a high prevalence of premature coronary artery disease. We hypothesized that HDL of FH patients might have a modified protein composition and investigated the proteomic signature of HDL obtained from FH patients and their unaffected relatives. HDLs were characterized by 2D electrophoresis/MS in 10 families from the SAFEHEART cohort (3 individuals/family: 2 with genetic FH diagnosis and 1 non-FH relative) clinically characterized and treated as per guidelines.WAT apoC-I secretion: role in delayed chylomicron clearance in vivo and ex vivo in WAT in obese subjects
Reduced white adipose tissue (WAT) LPL activity delays plasma clearance of TG-rich lipoproteins (TRLs). We reported the secretion of apoC-I, an LPL inhibitor, from WAT ex vivo in women. Therefore we hypothesized that WAT-secreted apoC-I associates with reduced WAT LPL activity and TRL clearance. WAT apoC-I secretion averaged 86.9 ± 31.4 pmol/g/4 h and 74.1 ± 36.6 pmol/g/4 h in 28 women and 11 men with BMI ≥27 kg/m2, respectively, with no sex differences. Following the ingestion of a 13C-triolein-labeled high-fat meal, subjects with high WAT apoC-I secretion (above median) had delayed postprandial plasma clearance of dietary TRLs, assessed from plasma 13C-triolein-labeled TGs and apoB48.PCSK9 inhibition-mediated reduction in Lp(a) with evolocumab: an analysis of 10 clinical trials and the LDL receptor's role
Lipoprotein (a) [Lp(a)] is independently associated with CVD risk. Evolocumab, a monoclonal antibody (mAb) to proprotein convertase subtilisin/kexin type 9 (PCSK9), decreases Lp(a). The potential mechanisms were assessed. A pooled analysis of Lp(a) and LDL cholesterol (LDL-C) in 3,278 patients from 10 clinical trials (eight phase 2/3; two extensions) was conducted. Within each parent study, biweekly and monthly doses of evolocumab statistically significantly reduced Lp(a) at week 12 versus control (P < 0.001 within each study); pooled median (quartile 1, quartile 3) percent reductions were 24.7% (40.0, 3.6) and 21.7% (39.9, 4.2), respectively.Effects of angiopoietin-like protein 3 deficiency on postprandial lipid and lipoprotein metabolism
The consequences of angiopoietin-like protein 3 (ANGPTL3) deficiency on postprandial lipid and lipoprotein metabolism has not been investigated in humans. We studied 7 homozygous (undetectable circulating ANGPTL3 levels) and 31 heterozygous (50% of circulating ANGPTL3 levels) subjects with familial combined hypolipidemia (FHBL2) due to inactivating ANGPTL3 mutations in comparison with 35 controls. All subjects were evaluated at fasting and during 6 h after a high fat meal. Postprandial lipid and lipoprotein changes were quantified by calculating the areas under the curve (AUCs) using the 6 h concentration data.In silico modeling of the dynamics of low density lipoprotein composition via a single plasma sample
Lipoproteins play a key role in the development of CVD, but the dynamics of lipoprotein metabolism are difficult to address experimentally. This article describes a novel two-step combined in vitro and in silico approach that enables the estimation of key reactions in lipoprotein metabolism using just one blood sample. Lipoproteins were isolated by ultracentrifugation from fasting plasma stored at 4°C. Plasma incubated at 37°C is no longer in a steady state, and changes in composition may be determined.Disialylated apolipoprotein C-III proteoform is associated with improved lipids in prediabetes and type 2 diabetes
The apoC-III proteoform containing two sialic acid residues (apoC-III2) has different in vitro effects on lipid metabolism compared with asialylated (apoC-III0) or the most abundant monosialylated (apoC-III1) proteoforms. Cross-sectional and longitudinal associations between plasma apoC-III proteoforms (by mass spectrometric immunoassay) and plasma lipids were tested in two randomized clinical trials: ACT NOW, a study of pioglitazone in subjects with impaired glucose tolerance (n = 531), and RACED (n = 296), a study of intensive glycemic control and atherosclerosis in type 2 diabetes patients.Reduction in lipoprotein-associated apoC-III levels following volanesorsen therapy: phase 2 randomized trial results
Elevated apoC-III levels predict increased cardiovascular risk when present on LDL and HDL particles. We developed novel high-throughput chemiluminescent ELISAs that capture apoB, lipoprotein (a) [Lp(a)], and apoA-I in plasma and then detect apoC-III on these individual lipoproteins as apoCIII-apoB, apoCIII-Lp(a), and apoCIII-apoAI complexes, respectively. We assessed the effects on these complexes of placebo or 100–300 mg volanesorsen, a generation 2.0+ antisense drug that targets apoC3 mRNA in patients with hypertriglyceridemia, including familial chylomicronemia syndrome (n = 3), volanesorsen monotherapy (n = 51), and as add-on to fibrate (n = 26), treated for 85 days and followed for 176 days.Detection and confirmation of serum lipid biomarkers for preeclampsia using direct infusion mass spectrometry
Despite substantial research, the early diagnosis of preeclampsia remains elusive. Lipids are now recognized to be involved in regulation and pathophysiology of some disease. Shotgun lipidomic studies were undertaken to determine whether serum lipid biomarkers exist that predict preeclampsia later in the same in pregnancy. A discovery study was performed using sera collected at 12–14 weeks pregnancy from 27 controls with uncomplicated pregnancies and 29 cases that later developed preeclampsia. Lipids were extracted and analyzed by direct infusion into a TOF mass spectrometer.Population and assay thresholds for the predictive value of lipoprotein (a) for coronary artery disease: the EPIC-Norfolk Prospective Population Study
Variable agreement exists between different lipoprotein (a) [Lp(a)] measurement methods, but their clinical relevance remains unclear. The predictive value of Lp(a) measured by two different assays [Randox and University of California, San Diego (UCSD)] was determined in 623 coronary artery disease (CAD) cases and 948 controls in a case-control study within the EPIC-Norfolk Prospective Population Study. Participants were divided into sex-specific quintiles, and by Lp(a) <50 versus ∼50 mg/dl, which represents the 80th percentile in northern European subjects.Global molecular analysis and APOE mutations in a cohort of autosomal dominant hypercholesterolemia patients in France
Autosomal dominant hypercholesterolemia (ADH) is a human disorder characterized phenotypically by isolated high-cholesterol levels. Mutations in the low density lipoprotein receptor (LDLR), APOB, and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes are well known to be associated with the disease. To characterize the genetic background associated with ADH in France, the three ADH-associated genes were sequenced in a cohort of 120 children and 109 adult patients. Fifty-one percent of the cohort had a possible deleterious variant in LDLR, 3.1% in APOB, and 1.7% in PCSK9.Effect of fish oil on monoepoxides derived from fatty acids during cardiac surgery
Our objective was to assess the dynamics of monoepoxides derived from polyunsaturated fatty acids (MEFAs), and their response to n-3 PUFA supplementation, in the setting of acute tissue injury and inflammation (cardiac surgery) in humans. Patients (479) undergoing cardiac surgery in three countries were randomized to perioperative fish oil (EPA + DHA; 8–10 g over 2–5 days preoperatively, then 2 g/day postoperatively) or placebo (olive oil). Plasma MEFAs derived from n-3 and n-6 PUFAs were measured 2 days postoperatively.Associations of human retinal very long-chain polyunsaturated fatty acids with dietary lipid biomarkers
The human retina is well-known to have unique lipid profiles enriched in long-chain polyunsaturated fatty acids (LC-PUFAs) and very long-chain polyunsaturated fatty acids (VLC-PUFAs) that appear to promote normal retinal structure and function, but the influence of diet on retinal lipid profiles in health and disease remains controversial. In this study, we examined two independent cohorts of donor eyes and related their retinal lipid profiles with systemic biomarkers of lipid intake. We found that serum and red blood cell lipids, and to a lesser extent orbital fat, are indeed excellent biomarkers of retinal lipid content and n-3/n-6 ratios in both the LC-PUFA and VLC-PUFA series.Associations between intensive diabetes therapy and NMR-determined lipoprotein subclass profiles in type 1 diabetes
Our objective is to define differences in circulating lipoprotein subclasses between intensive versus conventional management of type 1 diabetes during the randomization phase of the Diabetes Control and Complications Trial (DCCT). NMR-determined lipoprotein subclass profiles (NMR-LSPs), which estimate molar subclass concentrations and mean particle diameters, were determined in 1,294 DCCT subjects after a median of 5 years (interquartile range: 4–6 years) of randomization to intensive or conventional diabetes management.Multiple susceptibility loci at chromosome 11q23.3 are associated with plasma triglyceride in East Asians
Genetic studies of plasma TG levels have identified associations with multiple candidate loci on chromosome11q23.3, which harbors a number of genes, including BUD13, ZNF259, and APOA5-A4-C3-A1. This study aimed to examine whether these multiple candidate genes on the 11q23.3 regions exert independent effects on TG levels or whether their effects are confounded by linkage disequilibrium (LD). We performed a genome-wide association study and consequent fine-mapping analyses on TG levels in two Korean population-based cohorts: the Korea Association Resource study (n = 8,223) and the Healthy Twin study (n = 1,735).Cytochrome P450-derived epoxyeicosatrienoic acids and coronary artery disease in humans: a targeted metabolomics study
Cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) exhibit potent cardiovascular protective effects in preclinical models, and promoting the effects of EETs has emerged as a potential therapeutic strategy for coronary artery disease (CAD). The relationship between circulating EET levels and CAD extent in humans, however, remains unknown. A panel of free (unesterified) plasma eicosanoid metabolites was quantified in 162 patients referred for coronary angiography, and associations with extent of CAD [no apparent CAD (N = 39), nonobstructive CAD (N = 51), and obstructive CAD (N = 72)] were evaluated.Characterization of circulating APOL1 protein complexes in African Americans
APOL1 gene renal-risk variants are associated with nephropathy and CVD in African Americans; however, little is known about the circulating APOL1 variant proteins which reportedly bind to HDL. We examined whether APOL1 G1 and G2 renal-risk variant serum concentrations or lipoprotein distributions differed from nonrisk G0 APOL1 in African Americans without nephropathy. Serum APOL1 protein concentrations were similar regardless of APOL1 genotype. In addition, serum APOL1 protein was bound to protein complexes in two nonoverlapping peaks, herein referred to as APOL1 complex A (12.2 nm diameter) and complex B (20.0 nm diameter).Reduction of serum FABP4 level by sitagliptin, a DPP-4 inhibitor, in patients with type 2 diabetes mellitus
Fatty acid binding protein 4 (FABP4), also known as adipocyte FABP or aP2, is secreted from adipocytes in association with lipolysis as a novel adipokine, and elevated serum FABP4 level is associated with obesity, insulin resistance, and atherosclerosis. However, little is known about the modulation of serum FABP4 level by therapeutic drugs. Sitagliptin (50 mg/day), a dipeptidyl peptidase 4 (DPP-4) inhibitor that increases glucagon-like peptide 1 (GLP-1), was administered to patients with type 2 diabetes (n = 24) for 12 weeks.Statin action favors normalization of the plasma lipidome in the atherogenic mixed dyslipidemia of MetS: potential relevance to statin-associated dysglycemia
The impact of statin treatment on the abnormal plasma lipidome of mixed dyslipidemic patients with metabolic syndrome (MetS), a group at increased risk of developing diabetes, was evaluated. Insulin-resistant hypertriglyceridemic hypertensive obese males (n = 12) displaying MetS were treated with pitavastatin (4 mg/day) for 180 days; healthy normolipidemic age-matched nonobese males (n = 12) acted as controls. Statin treatment substantially normalized triglyceride (−41%), remnant cholesterol (−55%), and LDL-cholesterol (−39%), with minor effect on HDL-cholesterol (+4%).Enhancement of lipid peroxidation and its amelioration by vitamin E in a subject with mutations in the SBP2 gene
Selenocysteine (Sec) insertion sequence-binding protein 2 (SBP2) is essential for the biosynthesis of Sec-containing proteins, termed selenoproteins. Subjects with mutations in the SBP2 gene have decreased levels of several selenoproteins, resulting in a complex phenotype. Selenoproteins play a significant role in antioxidative defense, and deficiencies in these proteins can lead to increased oxidative stress. However, lipid peroxidation and the effects of antioxidants in subjects with SBP2 gene mutations have not been studied.Glucagon receptor antagonism induces increased cholesterol absorption
Glucagon and insulin have opposing action in governing glucose homeostasis. In type 2 diabetes mellitus (T2DM), plasma glucagon is characteristically elevated, contributing to increased gluconeogenesis and hyperglycemia. Therefore, glucagon receptor (GCGR) antagonism has been proposed as a pharmacologic approach to treat T2DM. In support of this concept, a potent small-molecule GCGR antagonist (GRA), MK-0893, demonstrated dose-dependent efficacy to reduce hyperglycemia, with an HbA1c reduction of 1.5% at the 80 mg dose for 12 weeks in T2DM.Modification of platelet proteins by malondialdehyde: prevention by dicarbonyl scavengers
The thromboxane synthase converts prostaglandin H2 to thromboxane A2 and malondialdehyde (MDA) in approximately equimolar amounts. A reactive dicarbonyl, MDA forms covalent adducts of amino groups, including the ε-amine of lysine, but the importance of this reaction in platelets was unknown. Utilizing a novel LC/MS/MS method for analysis of one of the MDA adducts, the dilysyl-MDA cross-link, we demonstrated that dilysyl-MDA cross-links in human platelets are formed following platelet activation via the cyclooxygenase (COX)-1/thromboxane synthase pathway.HDL-apolipoprotein A-I exchange is independently associated with cholesterol efflux capacity
HDL is the primary mediator of cholesterol mobilization from the periphery to the liver via reverse cholesterol transport (RCT). A critical first step in this process is the uptake of cholesterol from lipid-loaded macrophages by HDL, a function of HDL inversely associated with prevalent and incident cardiovascular disease. We hypothesized that the dynamic ability of HDL to undergo remodeling and exchange of apoA-I is an important and potentially rate-limiting aspect of RCT. In this study, we investigated the relationship between HDL-apoA-I exchange (HAE) and serum HDL cholesterol (HDL-C) efflux capacity.Protective associations of HDL with blood-brain barrier injury in multiple sclerosis patients
The purpose of this work was to investigate the associations of serum cholesterol and apolipoproteins with measures of blood-brain barrier (BBB) permeability and CNS inflammation following the first clinical demyelinating event. This study included 154 patients [67% female; age, 29.5 ± 8.2 years (mean ± SD)] enrolled in a multi-center study of interferon β1-a treatment following the first demyelinating event. Blood and cerebrospinal fluid (CSF) were obtained at screening prior to treatment. A comprehensive serum lipid profile and multiple surrogate markers of BBB breakdown and CNS immune activity were obtained.Omental adipocyte hypertrophy relates to coenzyme Q10 redox state and lipid peroxidation in obese women
Occurrence of oxidative stress in white adipose tissues contributes to its dysfunction and the development of obesity-related metabolic complications. Coenzyme Q10 (CoQ10) is the single lipophilic antioxidant synthesized in humans and is essential for electron transport during mitochondrial respiration. To understand the role of CoQ10 in adipose tissue physiology and dysfunction, the abundance of the oxidized and reduced (CoQ10red) isoforms of the CoQ10 were quantified in subcutaneous and omental adipose tissues of women covering the full range of BMI (from 21.5 to 53.2 kg/m2).Targeted next-generation sequencing to diagnose disorders of HDL cholesterol
A low level of HDL cholesterol (HDL-C) is a common clinical scenario and an important marker for increased cardiovascular risk. Many patients with very low or very high HDL-C have a rare mutation in one of several genes, but identification of the molecular abnormality in patients with extreme HDL-C is rarely performed in clinical practice. We investigated the accuracy and diagnostic yield of a targeted next-generation sequencing (NGS) assay for extreme levels of HDL-C. We developed a targeted NGS panel to capture the exons, intron/exon boundaries, and untranslated regions of 26 genes with highly penetrant effects on plasma lipid levels.Cardiolipin fingerprinting of leukocytes by MALDI-TOF/MS as a screening tool for Barth syndrome
Barth syndrome (BTHS), an X-linked disease associated with cardioskeletal myopathy, neutropenia, and organic aciduria, is characterized by abnormalities of cardiolipin (CL) species in mitochondria. Diagnosis of the disease is often compromised by lack of rapid and widely available diagnostic laboratory tests. The present study describes a new method for BTHS screening based on MALDI-TOF/MS analysis of leukocyte lipids. This generates a “CL fingerprint” and allows quick and simple assay of the relative levels of CL and monolysocardiolipin species in leukocyte total lipid profiles.The n-3 long-chain PUFAs modulate the impact of the GCKR Pro446Leu polymorphism on triglycerides in adolescents
Dietary n-3 long-chain PUFAs (LC-PUFAs) are associated with improvement in the parameters of the metabolic syndrome (MetS). Glucokinase regulatory protein (GCKR) is a key protein regulating intracellular glucose disposal. Our aim was to investigate: i) the relationship between the GCKR rs1260326 (Pro446Leu) polymorphism and parameters of the MetS; and ii) a potential influence of n-3 and n-6 LC-PUFA levels on this relationship in the HELENA study (1,155 European adolescents). Linear regression analyses were performed to study the association between rs1260326 and the outcomes of interest.Increased palmitate intake: higher acylcarnitine concentrations without impaired progression of β-oxidation
Palmitic acid (PA) is associated with higher blood concentrations of medium-chain acylcarnitines (MCACs), and we hypothesized that PA may inhibit progression of FA β-oxidation. Using a cross-over design, 17 adults were fed high PA (HPA) and low PA/high oleic acid (HOA) diets, each for 3 weeks. The [1-13C]PA and [13-13C]PA tracers were administered with food in random order with each diet, and we assessed PA oxidation (PA OX) and serum AC concentration to determine whether a higher PA intake promoted incomplete PA OX.Bioactive products formed in humans from fish oils
Resolvins, maresins, and protectins can be formed from fish oils. These specialized pro-resolving mediators (SPMs) have been implicated in the resolution of inflammation. Synthetic versions of such SPMs exert anti-inflammatory effects in vitro and when administered to animal models. However, their importance as endogenous products formed in sufficient amounts to exert anti-inflammatory actions in vivo remains speculative. We biased our ability to detect SPMs formed in healthy volunteers by supplementing fish oil in doses shown previously to influence blood pressure and platelet aggregation under placebo-controlled conditions.A novel truncated form of apolipoprotein A-I transported by dense LDL is increased in diabetic patients
Diabetic (DM) patients have exacerbated atherosclerosis and high CVD burden. Changes in lipid metabolism, lipoprotein structure, and dysfunctional HDL are characteristics of diabetes. Our aim was to investigate whether serum ApoA-I, the main protein in HDL, was biochemically modified in DM patients. By using proteomic technologies, we have identified a 26 kDa ApoA-I form in serum. MS analysis revealed this 26 kDa form as a novel truncated variant lacking amino acids 1-38, ApoA-IΔ(1-38). DM patients show a 2-fold increase in ApoA-IΔ(1-38) over nondiabetic individuals.Genetic meta-analysis of 15,901 African Americans identifies variation in EXOC3L1 is associated with HDL concentration
Meta-analyses of European populations has successfully identified genetic variants in over 150 loci associated with lipid levels, but results from additional ethnicities remain limited. Previously, we reported two novel lipid loci identified in a sample of 7,657 African Americans using a gene-centric array including 50,000 SNPs in 2,100 candidate genes. Initial discovery and follow-up of signals with P < 10−5 in additional African American samples confirmed CD36 and ICAM1. Using an additional 8,244 African American female samples from the Women's Health Initiative SNP Health Association Resource genome-wide association study dataset, we further examined the previous meta-analyses results by attempting to replicate 20 additional putative lipid signals with P < 10−4.Levels of atherogenic lipoproteins are unexpectedly reduced in interstitial fluid from type 2 diabetes patients
At a given level of serum cholesterol, patients with T2D have an increased risk of developing atherosclerosis compared with nondiabetic subjects. We hypothesized that T2D patients have an increased interstitial fluid (IF)-to-serum gradient ratio for LDL, due to leakage over the vascular wall. Therefore, lipoprotein profiles in serum and IF from 35 T2D patients and 35 healthy controls were assayed using fast performance liquid chromatography. The IF-to-serum gradients for VLDL and LDL cholesterol, as well as for apoB, were clearly reduced in T2D patients compared with healthy controls.PLTP activity inversely correlates with CAAD: effects of PON1 enzyme activity and genetic variants on PLTP activity
Recent studies have failed to demonstrate a causal cardioprotective effect of HDL cholesterol levels, shifting focus to the functional aspects of HDL. Phospholipid transfer protein (PLTP) is an HDL-associated protein involved in reverse cholesterol transport. This study sought to determine the genetic and nongenetic predictors of plasma PLTP activity (PLTPa), and separately, to determine whether PLTPa predicted carotid artery disease (CAAD). PLTPa was measured in 1,115 European ancestry participants from a case-control study of CAAD.IL-6 blockade by monoclonal antibodies inhibits apolipoprotein (a) expression and lipoprotein (a) synthesis in humans
Lipoprotein (a) [Lp(a)] is a highly atherogenic lipid particle. Although earlier reports suggested that Lp(a) levels are mostly determined by genetic factors, several recent studies have revealed that Lp(a) induction is also caused by chronic inflammation. Therefore, we aimed to examine whether cytokine blockade by monoclonal antibodies may inhibit Lp(a) metabolism. We found that interleukin 6 (IL-6) blockade by tocilizumab (TCZ) reduced Lp(a) while TNF-α-inhibition by adalimumab in humans had no effect.Lipidomic changes of LDL in overweight and moderately hypercholesterolemic subjects taking phytosterol- and omega-3-supplemented milk
The benefits of dietary phytosterols (PhySs) and long-chain n-3 PUFA (ω3) have been linked to their effects as cholesterol- and triglyceride (TGL)-lowering agents. However, it remains unknown whether these compounds have further metabolic effects on LDL lipid composition. Here, we studied the effects of PhyS- or ω3-supplemented low-fat milk (milk) on the LDL-lipidome. Overweight and moderately hypercholesterolemic subjects (n = 32) were enrolled in a two-arm longitudinal crossover study. Milk (250 ml/day), enriched with either 1.57 g PhyS or 375 mg ω3 (EPA + DHA), was given to the participants during two sequential 28 day intervention periods.Serum lipoprotein (a) concentrations are inversely associated with T2D, prediabetes, and insulin resistance in a middle-aged and elderly Chinese population
Lipoprotein (a) [Lp(a)], an LDL-like particle, has been proposed as a causal risk factor for CVD among general populations. Meanwhile, both serum Lp(a) and diabetes increase the risk of CVD. However, the relationship between serum Lp(a) and T2D is poorly characterized, especially in the Asian population. Therefore, we conducted a cross-sectional study in 10,122 participants aged 40 years or older in Jiading District, Shanghai, China. Our study found that the prevalence of T2D was decreased from 20.9% to 15.0% from the lowest quartile to the highest quartile of serum Lp(a) concentrations (P for trend <0.0001).Ext1 heterozygosity causes a modest effect on postprandial lipid clearance in humans
Elevated nonfasting TG-rich lipoprotein levels are a risk factor for CVD. To further evaluate the relevance of LDL-receptor (LDLr) pathway and heparan sulfate proteoglycans (HSPGs) in TG homeostasis, we analyzed fasting and postprandial TG levels in mice bearing combined heterozygous mutations in both Exostosin (Ext) 1 and Ldlr, in subjects with hereditary multiple exostosis (HME) due to a heterozygous loss-of-function mutation in EXT1 or EXT2 (N = 13), and in patients with heterozygous mutations in LDLR [familial hypercholesterolemia (FH)] and SNPs in major HSPG-related genes (n = 22).Plasma cholesterol efflux capacity from human THP-1 macrophages is reduced in HIV-infected patients: impact of HAART
The capacity of HDL to remove cholesterol from macrophages is inversely associated with the severity of angiographic coronary artery disease. The effect of human immunodeficiency virus (HIV) infection or its treatment on the ability of HDL particles to stimulate cholesterol efflux from human macrophages has never been studied. We evaluated the capacity of whole plasma and isolated HDL particles from HIV-infected subjects (n = 231) and uninfected controls (n = 200), as well as in a subset of 41 HIV subjects receiving highly active antiretroviral therapy (HAART) to mediate cholesterol efflux from human macrophages.Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA
Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months.Effects of n-3 FA supplementation on the release of proresolving lipid mediators by blood mononuclear cells: the OmegAD study
Specialized proresolving mediators (SPMs) induce resolution of inflammation. SPMs are derivatives of n-3 and n-6 PUFAs and may mediate their beneficial effects. It is unknown whether supplementation with PUFAs influences the production of SPMs. Alzheimer's disease (AD) is associated with brain inflammation and reduced levels of SPMs. The OmegAD study is a randomized, double-blind, and placebo-controlled clinical trial on AD patients, in which placebo or a supplement of 1.7 g DHA and 0.6 g EPA was taken daily for 6 months.The implication of cigarette smoking and cessation on macrophage cholesterol efflux in coronary artery disease patients
We investigated ATP-binding cassette transporters A1/G1 expression and function in mediating cholesterol efflux by examining the macrophages of cigarette-smoking patients with coronary artery disease (CAD) before and after smoking abstinence. Peripheral blood monocyte cells were collected from nonsmokers (n = 17), non-CAD (NCAD) smokers (n = 35), and CAD smokers (n = 32) before and after 3 months of smoking cessation. We found that the ABCA1 expression level was lower in macrophages from NCAD and CAD smokers than from nonsmokers at baseline.Biomarkers of NAFLD progression: a lipidomics approach to an epidemic
The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. Recognition and timely diagnosis of these different stages, particularly NASH, is important for both potential reversibility and limitation of complications. Liver biopsy remains the clinical standard for definitive diagnosis. Diagnostic tools minimizing the need for invasive procedures or that add information to histologic data are important in novel management strategies for the growing epidemic of NAFLD.
