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Carbon dots are emerging nanoparticles (NPs) with tremendous applications, especially in the biomedical field. Herein is reported the first quantitative proteomic analysis of the protein corona formed on CDs with different surface charge properties. Four CDs were synthesized from citric acid and various amine group-containing passivation reagents, resulting in cationic NPs with increasing zeta (ζ)-potential and density of positive charges. After CD contact with serum, we show that protein corona identity is influenced by CD surface charge properties, which in turn impacts CD uptake and viability loss in macrophages. In particular, CDs with high ζ-potential (+30 mV) and charge density (2 μmol mg

Targeted regional optimization (TRO), a partial resuscitative endovascular balloon occlusion of the aorta strategy, may mitigate distal ischemia and extend the window of effectiveness for this adjunct. An automated device may allow greater control and precise regulation of flow past the balloon, while being less resource-intensive. The objective of this study was to assess the technical feasibility of the novel advanced partial occlusion controller (APOC) in achieving TRO at multiple distal pressures.Female swine (n = 48, 68.1 ± 0.7 kg) were randomized to a target distal mean arterial pressure (MAP) of 25 mm Hg, 35 mm Hg, or 45 mm Hg by either manual (MAN) or APOC regulation (n = 8 per group). Uncontrolled hemorrhage was generated by liver laceration. Targeted regional optimization was performed for 85 minutes, followed by surgical control and a 6-hour critical care phase. Proximal and distal MAP and flow rates were measured continuously.At a target distal MAP of 25 mm Hg, there was no difference in the MAP attained (APOC: 26.2 ± 1.05 vs. MAN: 26.1 ± 1.78 mm Hg) but the APOC had significantly less deviance (10.9%) than manual titration (14.9%, p0.0001). Similarly, at a target distal MAP of 45 mm Hg, there was no difference in mean pressure (44.0 ± 0.900 mm Hg vs. 45.2 ± 1.31 mm Hg) but APOC had less deviance (9.34% vs. 11.9%, p0.0001). There was no difference between APOC and MAN in mean (34.6 mm Hg vs. 33.7 mm Hg) or deviance (9.95% vs. 10.4%) at a target distal MAP of 35 mm Hg, respectively. The APOC made on average 77 balloon volume adjustments per experiment compared with 29 by manual titrations.The novel APOC consistently achieved and sustained precisely regulated TRO across all groups and demonstrated reduced deviance at the 25 mm Hg and 45 mm Hg groups compared with manual titration.

Background Apolipoprotein CIII (apoCIII) is associated with triglyceride-rich lipoprotein metabolism and has emerged as independent marker for risk of cardiovascular disease. The objective was to test whether apoCIII is regulated postprandially and whether apoCIII concentrations in native and chylomicron-free serum predict future cardiovascular events in patients with stable coronary artery disease (CAD). Methods ApoCIII concentrations were measured in native and chylomicron-free serum in the fasting state and after a standardized oral fat load test in 195 patients with stable CAD. Clinical follow-up was 48 months. Chylomicron-free serum was prepared by ultracentrifugation (18,000 rpm, 3 h). The log-rank test and Cox regression analyses were used to investigate the association of apoCIII with recurrent cardiovascular events. Results Of the 195 patients included, 92 had a cardiovascular event, and 103 did not. 97% were treated with a statin. No significant changes in apoCIII concentration were observed after the oral fat load test. The apoCIII concentration was associated with event-free survival independent of conventional risk factors. This association reached statistical significance only for apoCIII concentration measured in chylomicron-free serum (hazard ratio [95% confidence interval] for apoCIII above the mean: postprandial: 1.67 (1.06–2.29), P = 0.028, fasting: 2.09 (1.32–3.32), P = 0.002), but not for apoCIII concentration measured in native serum (postprandial: 1.47 [0.89–2.43], P = 0.133, fasting: 1.56 [0.95–2.58], P = 0.081). The effects were independent of other risk factors. Conclusions ApoCIII concentrations in chylomicron-free serum are independently associated with event-free survival in patients with CAD both in fasting and postprandial state. This findings support considering apoCIII for risk assessment and attempting to test the hypothesis that lowering apoCIII reduces residual cardiovascular risk. Take home message Apolipoprotein CIII concentration measured in chylomicron-free serum predicts recurrent cardiovascular events in patients with stable coronary artery disease. Trial registration The trial which included the participants of this study was registered at https://clinicaltrials.gov (NCT00628524) on March 5, 2008.

Purpose To evaluate the prevalence, characteristics, and respiratory arousal threshold (ArTH) of Chinese patients with positional obstructive sleep apnea (POSA) according to the Cartwright Classification (CC) and Amsterdam Positional Obstructive Sleep Apnea Classification (APOC). Methods A large-scale cross-sectional study was conducted in our sleep center from 2007 to 2018 to analyze the clinical and polysomnography (PSG) data of Chinese POSA patients. Low ArTH was defined based on PSG indices. Results Of 5,748 OSA patients, 36.80% met the CC criteria, and 42.88% the APOC criteria, for POSA. The prevalence of POSA was significantly higher in women than men (40.21% and 46.52% vs. 36.13% and 42.18% for CC and APOC, respectively). Chinese POSA patients had a lower apnea hypopnea index (AHI) and lower oxygen desaturation index, shorter duration of oxygen saturation (SaO2) 2 and higher lowest SaO2 value compared to subjects with non-positional OSA (NPOSA). More than 40% of the POSA patients had a low ArTH; the proportion was extremely high in the supine-isolated-POSA (si-POSA) group and APOC I group. In multivariate logistic regression analyses, higher mean SaO2 and lower AHI during sleep were positive predictors of POSA. Conclusions According to the CC and APOC criteria, more than 1/3 of our Chinese subjects with OSA had POSA. Chinese POSA patients had less severe OSA and nocturnal hypoxia. Compared to NPOSA patients, significantly more patients with POSA had a low ArTH. A low ArTH may be an important endotype in the pathogenesis of POSA, especially in patients with si-POSA and APOC I. Further studies are necessary to develop personalized management strategies for POSA patients. Trial registration: Chinese Clinical Trial Registry; URL: http://www.chictr.org.cn; No. ChiCTR1900025714 (retrospectively registered).

Purpose of review Sepsis is a common syndrome of multiorgan system dysfunction caused by a dysregulated inflammatory response to an infection and is associated with high rates of mortality. Plasma lipid and lipoprotein levels and composition change profoundly during sepsis and have emerged as both biomarkers and potential therapeutic targets for this condition. The purpose of this article is to review recent progress in the understanding of the molecular regulation of lipid metabolism during sepsis. Recent findings Patients who experience greater declines in high-density lipoprotein during sepsis are at much greater risk of succumbing to organ failure and death. Although the causality of these findings remains unclear, all lipoprotein classes can sequester and prevent the excessive inflammation caused by pathogen-associated lipids during severe infections such as sepsis. This primordial innate immune function has been best characterized for high-density lipoproteins. Most importantly, results from human genetics and preclinical animal studies have suggested that several lipid treatment strategies, initially designed for atherosclerosis, may hold promise as therapies for sepsis. Summary Lipid and lipoprotein metabolism undergoes significant changes during sepsis. An improved understanding of the molecular regulation of these changes may lead to new opportunities for the treatment of sepsis.

Aims Recently, Apolipoprotein CIII (Apo-CIII) has gained remarkable attention since its overexpression has been strongly correlated to cardiovascular disease (CVD) occurrence. The aim of this review was to summarize the latest findings of Apo-CIII as a CVDs and diabetes risk factor, as well as the plausible mechanisms involved in the development of these pathologies, with particular emphasis on current clinical and dietetic therapies. Data synthesis Apo-CIII is a small protein (∼8.8 kDa) that, among other functions, inhibits lipoprotein lipase, a key enzyme in lipid metabolism. Apo-CIII plays a fundamental role in the physiopathology of atherosclerosis, type-1, and type-2 diabetes. Apo-CIII has become a potential clinical target to tackle these multifactorial diseases. Dietetic (omega-3 fatty acids, stanols, polyphenols, lycopene) and non-dietetic (fibrates, statins, and antisense oligonucleotides) therapies have shown promising results to regulate Apo-CIII and triglyceride levels. However, more information from clinical trials is required to validate it as a new target for atherosclerosis and diabetes types 1 and 2. Conclusions There are still several pathways involving Apo-CIII regulation that might be affected by bioactive compounds that need further research. The mechanisms that trigger metabolic responses following bioactive compounds consumption are mainly related to higher LPL expression and PPARα activation, although the complete pathways are yet to be elucidated.

BACKGROUND The aims of this study included 3 aspects: 1) assessing the expression of Apolipoprotein C1 (APOC1) in clear cell renal cell carcinoma (ccRCC) and normal groups; 2) evaluating the prognostic significance of APOC1 expression in the overall survival (OS) of ccRCC patients; and 3) exploring APOC1-related signaling pathways. MATERIAL AND METHODS The APOC1 expression value and clinical data of ccRCC patients were obtained from the cBioPortal database. We then evaluated the association of APOC1 expression with clinical characteristics of ccRCC patients. We also assessed the correlation between APOC1 expression and clinical outcome using Kaplan-Meier method. Our work then verified the independent prognostic factors of ccRCC by Cox regression analysis. Finally, the potential role of genes co-expressed with APOC1 was revealed via functional enrichment analysis. RESULTS Bioinformatic data revealed that APOC1 was expressed at higher levels in ccRCC tissue than in the normal group (all P

Background: Selected dyslipidemia guidelines recommend non-high-density lipoprotein-cholesterol (non-HDL-C) and apolipoprotein B (apoB) as secondary targets to the primary target of low-density lipoprotein-cholesterol (LDL-C). After considering 2 LDL-C estimates that differ in accuracy, we examined: (1) how frequently non-HDL-C guideline targets could change management; and (2) the utility of apoB targets after meeting LDL-C and non-HDL-C targets. Methods: We analyzed 2518 adults representative of the US population from the 2011 to 2012 National Health and Nutrition Examination Survey and 126 092 patients from the Very Large Database of Lipids study with apoB. We identified all individuals as well as those with high-risk clinical features, including coronary artery disease, diabetes mellitus, and metabolic syndrome who met very high- and high-risk guideline targets of LDL-C F ) and a novel, more accurate method (LDL-C N ). Next, we examined those not meeting non-HDL-C ( Results: A total of 7% to 9% and 31% to 36% of individuals had LDL-C F F N N F F or LDL-C N F or LDL-C N Conclusions: After more accurately estimating LDL-C, guideline-suggested non-HDL-C targets could alter management in only a small fraction of individuals, including those with coronary artery disease and other high-risk clinical features. Furthermore, current guideline-suggested apoB targets provide modest utility after meeting cholesterol targets. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01698489.

A one-off injection to reduce the risk of cardiovascular disease is now a prospect thanks to advances in gene editing. A one-off injection to reduce the risk of cardiovascular disease is now a prospect thanks to advances in gene editing.

Background Macrophage cholesterol efflux to high‐density lipoproteins ( HDLs ) is the first step of reverse cholesterol transport. The cholesterol efflux capacity ( CEC ) of HDL particles is a protective risk factor for coronary artery disease independent of HDL cholesterol levels. Using a genome‐wide association study approach, we aimed to identify pathways that regulate CEC in humans. Methods and Results We measured CEC in 5293 French Canadians. We tested the genetic association between 4 CEC measures and genotypes at >9 million common autosomal DNA sequence variants. These analyses yielded 10 genome‐wide significant signals ( P −9 ) representing 7 loci. Five of these loci harbor genes with important roles in lipid biology ( CETP , LIPC , LPL , APOA 1/C3/A4/A5 , and APOE /C1/C2/C4 ). Except for the APOE /C1/C2/C4 variant ( rs141622900 , P nonadjusted =1.0×10 −11 ; P adjusted =8.8×10 −9 ), the association signals disappear when correcting for HDL cholesterol and triglyceride levels. The additional 2 significant signals were near the PPP 1 CB / PLB 1 and RBFOX 3/ ENPP 7 genes. In secondary analyses, we considered candidate functional variants for 58 genes implicated in HDL biology, as well as 239 variants associated with blood lipid levels and/or coronary artery disease risk by genome‐wide association study . These analyses identified 27 significant CEC associations, implicating 5 additional loci ( GCKR , LIPG , PLTP , PPARA , and TRIB 1 ). Conclusions Our genome‐wide association study identified common genetic variation at the APOE /C1/C2/C4 locus as a major determinant of CEC that acts largely independently of HDL cholesterol. We predict that HDL ‐based therapies aiming at increasing CEC will be modulated by changes in the expression of apolipoproteins in this gene cluster.

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of morbidity and mortality in developed nations. Therapeutic modulation of dyslipidemia by inhibiting 3′-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is standard practice throughout the world. However, based on findings from Mendelian studies and genetic sequencing in prospective longitudinal cohorts from around the world, novel therapeutic targets regulating lipid and lipoprotein metabolism, such as apoprotein C3, angiopoietin-like proteins 3 and 4, and lipoprotein(a), have been identified. These targets may provide additional avenues to prevent and treat atherosclerotic disease. We therefore review these novel molecular targets by addressing available Mendelian and observational data, therapeutic agents in development, and early outcomes results.

AMAÇ: Bir çok memeli dokusunda ve mikroorganizmada bulunan prolidaz enziminin prolin aminoasit döngüsünde ve kollajen metabolizmasında işlevi vardır. Aynı zamanda oksidatif durumlarda da plazma prolidaz aktivitesi artmaktadır. ApoC2 hiperlipidemik kişilerde çok düşük yoğunluklu lipoprotein (VLDL) ve düşük yoğunluklu lipoprotein (LDL)'nin yapısına katılan apoliporotein çeşididir. Malondialdehid (MDA) ise hücresel hasarda gerçekleşen lipit peroksidasyon belirtecidir. Bu araştırmada çocukluk çağındaki hiperlipidemili hastalarda plazma prolidaz enzim aktivitesi, ApoC2 ve malondialdehidin bir arada incelenmesi ve birbirleri ile ilişkisinin araştırılması amaçlandı.GEREÇ VE YÖNTEM: Çalışmaya hiperlipidemi tanısı almış yaş ve cinsiyet uyumlu 40 hasta çocuk ve 40 sağlıklı çocuk dahil edildi. Prolidaz enzim aktivitesi modifiye Chinard yöntemiyle, MDA tiyobarbitürik asit tayin yöntemiyle, ApoC2 ise ELISA yöntemi kullanılarak ölçüldü.BULGULAR: Gruplar arasında yaş ve cinsiyet açısından anlamlı bir fark bulunmadı (p>0,05). Prolidaz enzim aktivitesi, ApoC2 ve malondialdehid düzeyleri hiperlipidemi grubunda kontrol grubuna göre anlamlı derecede yüksek bulundu (p 0,05). Prolidase enzyme activity, ApoC2 and malondialdehyde levels were significantly higher in hyperlipidemia group than control group (p

Cholesteryl ester transfer protein (CETP) mediates the transfer of HDL cholesteryl esters for triglyceride (TG) in VLDL/LDL. CETP inhibition, with anacetrapib, increases HDL-cholesterol, reduces LDL-cholesterol, and lowers TG levels. This study describes the mechanisms responsible for TG lowering by examining the kinetics of VLDL-TG, apoC-II, apoC-III, and apoE. Mildly hypercholesterolemic subjects were randomized to either placebo (N = 10) or atorvastatin 20 mg/qd (N = 29) for 4 weeks (period 1) followed by 8 weeks of anacetrapib, 100 mg/qd (period 2). Following each period, subjects underwent stable isotope metabolic studies to determine the fractional catabolic rates (FCRs) and production rates (PRs) of VLDL-TG and plasma apoC-II, apoC-III, and apoE. Anacetrapib reduced the VLDL-TG pool on a statin background due to an increased VLDL-TG FCR (29%; P = 0.002). Despite an increased VLDL-TG FCR following anacetrapib monotherapy (41%; P = 0.11), the VLDL-TG pool was unchanged due to an increase in the VLDL-TG PR (39%; P = 0.014). apoC-II, apoC-III, and apoE pool sizes increased following anacetrapib; however, the mechanisms responsible for these changes differed by treatment group. Anacetrapib increased the VLDL-TG FCR by enhancing the lipolytic potential of VLDL, which lowered the VLDL-TG pool on atorvastatin background. There was no change in the VLDL-TG pool in subjects treated with anacetrapib monotherapy due to an accompanying increase in the VLDL-TG PR.

Proteomic analyses facilitate the interpretation of molecular biomarker probes which are very\ud helpful in diagnosing schizophrenia. In the current study, we attempt to test whether potential\ud differences in plasma protein expressions in schizophrenia (SZ) and bipolar disorder (BD) are\ud associated with cognitive deficits and their underlying brain structures.\ud 42 plasma proteins of 29 SZ patients, 25 BD patients and 93 non-clinical controls were\ud quantified and analysed using multiple reaction monitoring (MRM) based triple quadrupole\ud mass spectrometry approach. We also computed group comparisons of protein expressions\ud between patients and controls, and between SZ and BD patients, as well. Potential associations\ud of protein levels with cognitive functioning (psychomotor speed, executive functioning,\ud crystallized intelligence) as well as underlying brain volume in the hippocampus were explored,\ud using bivariate correlation analyses.\ud The main finding of this study was that apolipoprotein (ApoC) expression differed\ud between patients and controls; and that these alterations in both disease groups were putatively\ud related to cognitive impairments as well as to hippocampus volumes. However, none of the\ud protein level differences were related to clinical symptom severity.\ud In summary, altered apolipoprotein expression in BD and SZ was linked to cognitive\ud decline and underlying morphological changes in both disorders. Our results suggest that the\ud detection of molecular patterns in association with cognitive performance and its underlying\ud brain morphology is of great importance for understanding of the pathological mechanisms of\ud SZ and BD, as well as for supporting the diagnosis and treatment of both disorders.

The apolipoprotein E-C1-C4-C2 gene cluster at 19q13.32 encodes four amphipathic apolipoproteins. The influence of APOE common polymorphisms on plasma lipid/lipoprotein profile, especially on LDL-related traits, is well recognized; however, little is known about the role of other genes/variants in this gene cluster. In this study, we evaluated the role of common and uncommon/rare genetic variation in this gene region on inter-individual variation in plasma lipoprotein levels in non-Hispanic Whites (NHWs) and African blacks (ABs). In the variant discovery step, the APOE, APOC1, APOC4, APOC2 genes were sequenced along with their flanking and hepatic control regions (HCR1 and HCR2) in 190 subjects with extreme HDL-C/TG levels. The next step involved the genotyping of 623 NHWs and 788 ABs for the identified uncommon/rare variants and common tagSNPs along with additional relevant SNPs selected from public resources, followed by association analyses with lipid traits. A total of 230 sequence variants, including 15 indels were identified, of which 65 were novel. A total of 70 QC-passed variants in NHWs and 108 QC-passed variants in ABs were included in the final association analyses. Single-site association analysis of SNPs with MAF>1% revealed 20 variants in NHWs and 24 variants in ABs showing evidence of association with at least one lipid trait, including several variants exhibiting independent associations from the established APOE polymorphism even after multiple-testing correction. Overall, our study has confirmed known associations and also identified novel associations in this genomic region with various lipid traits. Our data also support the contribution of both common and uncommon/rare variation in this gene region in affecting plasma lipid profile in the general population.

In human high-density lipoprotein (HDL) represents the major cholesterol carrying lipoprotein class in cord blood, while cholesterol is mainly carried by low-density lipoprotein in maternal serum. Additionally, to carrying cholesterol, HDL also associates with a range of proteins as cargo. We tested the hypothesis that fetal HDL carries proteins qualitatively and quantitatively different from maternal HDL. These differences then contribute to distinct HDL functionality in both circulations. Shotgun proteomics and biochemical analyses were used to assess composition/function of fetal and maternal HDL isolated from uncomplicated human pregnancies at term of gestation. The pattern of analyzed proteins that were statistically elevated in fetal HDL (apoE, proteins involved in coagulation, transport processes) suggests a particle characteristic for the light HDL2 sub-fraction. In contrast, proteins that were enriched in maternal HDL (apoL, apoF, PON1, apoD, apoCs) have been described almost exclusively in the dense HDL3 fraction and relevant to its anti-oxidative function and role in innate immunity. Strikingly, PON1 mass and activity were 5-fold lower (p

Concurrent fatty liver in hepatitis B virus (HBV)-infected patients without significant alcohol intake is a frequent and increasingly alarming problem because of the non-alcoholic fatty liver disease pandemic. The risk of HBV-related hepatocellular carcinoma (HCC) development was increased by concomitant obesity and diabetes. Direct evidence of the hepatocarcinogenic effect of fatty liver in chronic HBV remains elusive. We aimed to evaluate the risk of concurrent histologically proven fatty liver in HBV hepatocarcinogenesis.We conducted a retrospective cohort study on a liver biopsy cohort of HBV-infected patients without significant alcohol intake to evaluate the prevalence of concurrent histologically proven fatty liver and its association with subsequent HCC development. We also examined nine polymorphisms on six non-alcoholic fatty liver disease-related candidate genes (ADIPOQ, APOC3, GCKR, LEPR, PNPLA3, and PPARG).Among 270 HBV-infected patients, concurrent fatty liver was found in 107 patients (39.6%) and was associated with metabolic risks, cirrhosis (P = 0.016) and PNPLA3 rs738409 CG/GG genotype (P = 0.002). At a median follow-up of 79.9 months, 11 patients (4.1%) developed HCC, and nine of them had concurrent fatty liver. By multivariable Cox analysis, concurrent fatty liver (HR 7.27, 95% confidence interval: 1.52-34.76; P = 0.013), age, cirrhosis, and APOC3 rs2854116 TC/CC genotype (HR 3.93, 95% confidence interval: 1.30-11.84; P = 0.013) were independent factors predicting HCC development.Concurrent fatty liver is common in HBV-infected patients and an independent risk factor potentiating HBV-associated HCC development by 7.3-fold. The risk of HBV-related HCC is increased by APOC3 gene polymorphism, and further characterization is required by its role.

Contains fulltext : 171388.pdf (Publisher’s version ) (Closed access) OBJECTIVE: Gout is associated with dyslipidaemia. Association of the apolipoprotein A1-C3-A4 gene cluster with gout has previously been reported in a small study. To investigate a possible causal role for this locus in gout, we tested the association of genetic variants from APOA1 (rs670) and APOC3 (rs5128) with gout. METHODS: We studied data for 2452 controls and 2690 clinically ascertained gout cases of European and New Zealand Polynesian (Maori and Pacific) ancestry. Data were also used from the publicly available Atherosclerosis Risk in Communities study (n = 5367) and the Framingham Heart Study (n = 2984). Multivariate adjusted logistic and linear regression was used to test the association of single-nucleotide polymorphisms with gout risk, serum urate, triglyceride and high-density lipoprotein cholesterol (HDL-C). RESULTS: In Polynesians, the T-allele of rs670 (APOA1) increased (odds ratio, OR = 1.53, P = 4.9 x 10(-6)) and the G-allele of rs5128 (APOC3) decreased the risk of gout (OR = 0.86, P = 0.026). In Europeans, there was a strong trend to a risk effect of the T-allele for rs670 (OR = 1.11, P = 0.055), with a significant protective effect of the G-allele for rs5128 being observed after adjustment for triglycerides and HDL-C (OR = 0.81, P = 0.039). The effect at rs5128 was specific to males in both Europeans and Polynesians. Association in Polynesians was independent of any effect of rs670 and rs5128 on triglyceride and HDL-C levels. There was no evidence for association of either single-nucleotide polymorphism with serum urate levels (P 0.10). CONCLUSION: Our data, replicating a previous study, supports the hypothesis that the apolipoprotein A1-C3-A4 gene cluster plays a causal role in gout.

Triglyceride-rich lipoproteins (TRLs) that are modified during alimentary lipemia and their remnants are indicated to play an important role in the development of atherosclerosis. Although recent studies in transgenic and gene knock-out animal models have shed new light on the function of different apolipoproteins (apos) in the metabolism of TRLs and on their respective role in atherogenesis in these models, little is known about the compositional properties of human chylomicron remnants and very low density lipoprotein (VLDL). To address this issue, apos E, C-I, C-II, and C-III and lipids (triglycerides, phospholipids and cholesterol) were measured in Svedberg flotation rate (Sf) 60–400 and Sf 20–60 subfractions of VLDL and chylomicron remnants isolated from fasting and postprandial plasma samples in ten normotriglyceridemic men. VLDL was separated from chylomicron remnants by immunoaffinity chromatography using monoclonal antibodies (4G3 and 5E11) recognizing apoB-100 but not apoB-48 epitopes. The triglyceride, cholesterol and apoC-II contents of large (Sf 60–400) chylomicron remnants were significantly higher compared with large VLDL particles, while the small (Sf 20–60) chylomicron remnants contained significantly more apoC-II molecules but fewer apoC-I molecules than small VLDL. Whereas the apoC-III contents of large chylomicrons decreased, the apoC-III contents of large VLDL increased postprandially. The cholesterol to triglyceride ratio of large VLDL particles increased transiently by 50% in response to the oral fat load, whereas the cholesterol to triglyceride ratio of large chylomicron remnant particles and small TRL remnants increased 50–100% throughout the entire postprandial period. The specific alterations of the apolipoprotein and lipid composition of chylomicron remnants and VLDL particles observed during alimentary lipemia are likely to target these lipoprotein species differently to metabolic routes and to confer both endogenous and exogenous remnant lipoprotein roles in atherogenesis.—Björkegren, J., F. Karpe, R. W. Milne, and A. Hamsten. Differences in apolipoprotein and lipid composition between human chylomicron remnants and very low density lipoproteins isolated from fasting and postprandial plasma. J. Lipid Res. 1998. 39: 1412–1420.

The interactions between phospholipid molecules in suspensions have been studied by using mass spectrometry. Electrospray mass spectra of homogeneous preparations formed from three different phospholipid molecules demonstrate that under certain conditions interactions between 90 and 100 lipid molecules can be preserved. In the presence of apolipoprotein C-II, a phospholipid binding protein, a series of lipid molecules and the protein were observed in complexes. The specificity of binding was demonstrated by proteolysis; the resulting mass spectra reveal lipid-bound peptides that encompass the proposed lipid-binding domain. The mass spectra of heterogeneous suspensions and their complexes with apolipoprotein C-II demonstrate that the protein binds simultaneously to two different phospholipids. Moreover, when apolipoprotein C-II is added to lipid suspensions formed with local concentrations of the same lipid molecule, the protein is capable of remodeling the distribution to form one that is closer to a statistical arrangement. These observations demonstrate a capacity for apolipoprotein C-II to change the topology of the phospholipid surface. More generally, these results highlight the fact that mass spectrometry can be used to probe lipid interactions in both homogeneous and heterogeneous suspensions and demonstrate reorganization of the distribution of lipids upon surface binding of apolipoprotein C-II.

Objectives— Recently, we reported that exaggerated postprandial triglyceridemia in normolipidemic patients with coronary artery disease is associated with enrichment of remnant lipoproteins with apolipoprotein C-I (apoC-I). In this study, the number and composition of chylomicron remnants and very low density lipoproteins (VLDLs) were examined in 30 asymptomatic normolipidemic 50-year-old men with and without early carotid atherosclerotic lesions. Results and Methods— Intima-media thickness of the far wall of the common carotid artery was determined by B-mode ultrasound. Triglyceride-rich lipoproteins were subfractionated by density gradient ultracentrifugation and separated into VLDL and chylomicron remnant fractions by immunoaffinity chromatography. The postprandial triglyceridemia and increase in triglyceride-rich lipoprotein particle number (ie, apolipoprotein B concentrations) were not exaggerated in men with early atherosclerosis. In contrast, their large (Svedberg flotation rate 60 to 400) and small (Svedberg flotation rate 20 to 60) chylomicron remnants and VLDL were greatly enriched with apoC-I, and their small chylomicron remnants and VLDL particles were relatively enriched with cholesterol. Moreover, the number of apoC-I molecules on small chylomicron remnants was strongly associated with the degree of atherosclerosis. Conclusions— Early asymptomatic atherosclerosis in normolipidemic men without exaggerated postprandial triglyceridemia is associated with the enrichment of postprandial chylomicron and VLDL particles with apoC-I. Therefore, it is conceivable that the apoC-I content of lipoprotein remnants may serve as an early marker of coronary artery disease risk.

The incidence and the public health importance of diabetes mellitus are growing continuously. Despite the improvement observed in recent years, the leading cause of morbidity and mortality of diabetics are cardiovascular diseases. The diagnosis of diabetes mellitus constitutes such a high risk as the known presence of vascular disease. Diabetic dyslipidaemia is characterised by high fasting and postprandial triglyceride levels, low HDL level, and slightly elevated LDL-cholesterol with domination of atherogenic small dense LDL. These are not independent components of the atherogenic dyslipidaemia, but are closely linked to each other. Beside the known harmful effects of low HDL and small dense LDL, recent findings confirmed the atherogenicity of the triglyceride-rich lipoproteins and their remnants. It has been shown that the key of this process is the overproduction and delayed clearance of triglyceride-rich lipoproteins in the liver. In this metabolism the lipoprotein lipase has a determining role; its function is accelerated by ApoA5 and attenuated by ApoC3. The null mutations of the ApoC3 results in a reduced risk of myocardial infarction, the loss-of-function mutation of ApoA5 was associated with a 60% elevation of triglyceride level and 2.2-times increased risk of myocardial infarction. In case of diabetes mellitus, insulin resistance, obesity, metabolic syndrome and chronic kidney disease the non-HDL-cholesterol is a better marker of the risk than the LDL-cholesterol. Its value can be calculated by subtraction of HDL-cholesterol from total cholesterol. Target values of non-HDL-cholesterol can be obtained by adding 0.8 mmol/L to the LDL-cholesterol targets (this means 3.3 mmol/L in high, and 2.6 mmol/L in very high risk patients). The drugs of first choice in the treatment of diabetic dyslipidaemia are statins. Nevertheless, it is known that even if statin therapy is optimal (treated to target), a considerable residual (lipid) risk remains. For its reduction treatment of low HDL-cholesterol and high triglyceride levels is obvious by the administration of fibrates. In addition to statin therapy, fenofibrate can be recommended.

Context:Dyslipidemia increases the risk of cardiovascular disease in obesity. Peroxisome proliferator-activated receptor (PPAR)-δ agonists decrease plasma triglycerides and increase high-density lipoprotein (HDL)-cholesterol in humans.Objective:The aim of the study was to examine the effect of GW501516, a PPAR-δ agonist, on lipoprotein metabolism.Design, Setting, and Intervention:We conducted a randomized, double-blind, crossover trial of 6-wk intervention periods with placebo or GW501516 (2.5 mg/d), with 2-wk placebo washout between treatment periods.Participants:We recruited 13 dyslipidemic men with central obesity from the general community.Main Outcome Measures:We measured the kinetics of very low-density lipoprotein (VLDL)-, intermediate-density lipoprotein-, and low-density lipoprotein (LDL)-apolipoprotein (apo) B-100, plasma apoC-III, and high-density lipoprotein (HDL) particles (LpA-I and LpA-I:A-II).Results:GW501516 decreased plasma triglycerides, fatty acid, apoB-100, and apoB-48 concentrations. GW501516 decreased the concentrations of VLDL-apoB by increasing its fractional catabolism and of apoC-III by decreasing its production rate (P < 0.05). GW501516 reduced VLDL-to-LDL conversion and LDL-apoB production. GW501516 increased HDL-cholesterol, apoA-II, and LpA-I:A-II concentrations by increasing apoA-II and LpA-I:A-II production (P < 0.05). GW501516 decreased cholesteryl ester transfer protein activity, and this was paralleled by falls in the triglyceride content of VLDL, LDL, and HDL and the cholesterol content of VLDL and LDL.Conclusions:GW501516 increased the hepatic removal of VLDL particles, which might have resulted from decreased apoC-III concentration. GW501516 increased apoA-II production, resulting in an increased concentration of LpA-I:A-II particles. This study elucidates the mechanism of action of this PPAR-δ agonist on lipoprotein metabolism and supports its potential use in treating dyslipidemia in obesity.

Objective It has been shown that dietary whey protein accelerates glucose uptake by altering glycoregulatory enzyme activity in skeletal muscle. In the present study, we investigated the effect of dietary whey protein on endurance and glycogen resynthesis and attempted to identify plasma proteins that reflected the physical condition by a comprehensive proteomics approach. Methods Male c57BL/6 mice were divided into four groups: sedentary, sedentary with whey protein hydrolysate, exercise, and exercise with whey protein hydrolysate. The mice in the exercise groups performed treadmill running exercise five times per week for 4 wk. Protein profiling of plasma sample obtained from individuals was performed, as were measurements of endurance performance and the glycogen content of gastrocnemius muscle. Results After the training period, the endurance of mice fed the whey diet was improved compared with that of mice fed the control diet. Muscle glycogen content was significantly increased after 4 wk of exercise, and intake of whey protein led to a further increase in glycogen. Apolipoproteins A-II and C-I and β 2 -glycoprotein-1 were found to be altered by training combined with the intake of whey protein, without significant changes induced by exercise or whey protein alone. Conclusion Results of the present study suggest that these three proteins may be potential biomarkers of improved endurance and glycogen resynthesis and part of the mechanism that mediates the benefits of whey protein.

We have shown that expression of apolipoprotein (apo) C-III promotes VLDL secretion from transfected McA-RH7777 cells under lipid-rich conditions. To determine structural elements within apoC-III that confer to this function, we contrasted wild-type apoC-III with a mutant Ala23Thr originally identified in hypotriglyceridemia subjects. Although synthesis of [(3)H]glycerol-labeled TAG was comparable between cells expressing wild-type apoC-III (C3wt cells) or Ala23Thr mutant (C3AT cells), secretion of [(3)H]TAG from C3AT cells was markedly decreased. The lowered [(3)H]TAG secretion was associated with an inability of C3AT cells to assemble VLDL(1). Moreover, [(3)H]TAG within the microsomal lumen in C3AT cells was 60% higher than that in C3wt cells, yet the activity of microsomal triglyceride-transfer protein in C3AT cells was not elevated. The accumulated [(3)H]TAG in C3AT microsomal lumen was mainly associated with lumenal IDL/LDL-like lipoproteins. Phenotypically, this [(3)H]TAG fractionation profiling resembled what was observed in cells treated with brefeldin A, which at low dose specifically blocked the second-step VLDL(1) maturation. Furthermore, lumenal [(35)S]Ala23Thr protein accumulated in IDL/LDL fractions and was absent in VLDL fractions in C3AT cells. These results suggest that the presence of Ala23Thr protein in lumenal IDL/LDL particles might prevent effective fusion between lipid droplets and VLDL precursors. Thus, the current study reveals an important structural element residing within the N-terminal region of apoC-III that governs the second step VLDL(1) maturation.