Total Apo Research Articles

Consuming 12 eggs per week for 1 year does not alter serum lipids, lipoprotein cholesterol, or C‐reactive protein in older adults

Recent studies suggest that eating 1 or more eggs daily may increase an individual's blood total and LDL cholesterol levels thus increasing their risk of cardiovascular disease. The purpose of this study was to determine the effects of consuming 12 eggs per week for 1 year on blood lipids, lipoprotein cholesterol, apolipoprotein (apo) A‐1 and B, lipoprotein a (Lpa), and C‐reactive protein (CRP) levels, compared to people consuming no eggs of 1 year. Forty‐Five older adults (≥ 60 years of age) diagnosed with early age‐related macular degeneration (AMD) were placed into either the intervention (27) or control (18) group based on their willingness to consume eggs. On average, the Intervention group had slightly higher, but not significantly, serum total cholesterol (TC), LDL cholesterol (LDL‐C), triglycerides (TG), HDL cholesterol (HDL‐C), apo A‐1, and CRP levels compared to the Control group after the 12 months. Also, the Intervention group had slightly lower, but not significantly, serum Lpa levels and apo A‐1:apo B ratio compared to the Control group after the 12 months. Serum apo B levels were unchanged in both groups after the 12 months. Also within the Intervention group serum TC, LDL‐C, TG, and HDL‐C levels were slightly higher after 12 months of consuming 12 eggs per week; while within the Control serum TC, LDL‐C, and TG levels were slightly lower after 12 months of consuming no eggs compared to baseline but this was also not statistically significant. This study suggests that the consumption of 12 eggs per week for 1 year has no effect on serum lipids, lipoprotein cholesterol, apo A‐1, apo B, Lpa or CRP levels in older adults diagnosed with early AMD. The Egg Nutrition Center of the American Egg Board supported this research.

Concentration of apolipoprotein-E in high-density lipoproteins of human blood plasma

The aim of this study was to determine apolipoprotein (apo) E concentration in the high-density lipoprotein (HDL) fractions of normolipidemic subjects. ApoE concentrations in total blood plasma and HDL fractions were measured by an immunoturbidimetric method. We observed that the quantitative distribution of apoE among different lipoprotein classes depends on the total plasma apoE concentration: at low total plasma apoE concentration, a substantial amount of apoE was associated with HDL; an increase in total plasma apoE was accompanied by a more equal distribution of apoE among lipoprotein fractions. The concentration of apoE in the HDL fraction was stable and did not depend on the total plasma apoE concentration. Thus, the preservation of a constant concentration of apoE in HDL due to its redistribution among lipoprotein classes is a priority when total plasma apoE concentrations change. This feature should be considered at diagnosis and for the treatment of lipid disorders.

Association of theKLF14rs4731702 SNP and Serum Lipid Levels in the Guangxi Mulao and Han Populations

The objective of the present study was to detect the association of the rs4731702 single nucleotide polymorphism (SNP) and serum lipid levels in the Guangxi Mulao and Han populations. A total of 727 subjects of Mulao and 740 subjects of Han Chinese were included. Serum low-density lipoprotein cholesterol (LDL-C) and apolipoprotein (Apo) B levels were higher in Mulao than in Han (P < 0.05). The T allele carriers had higher serum LDL-C and ApoAI levels in Mulao, whereas they had lower high-density lipoprotein cholesterol (HDL-C) levels and ratio of ApoAI to ApoB in Han (P < 0.05) than the T allele noncarriers. Subgroup analyses showed that the T allele carriers had higher HDL-C, LDL-C, and ApoAI levels in Mulao males and lower ApoAI levels and ratio of ApoAI to ApoB in Han males than the T allele noncarriers. The subjects with TT genotype in Han females also had higher total cholesterol, LDL-C, ApoAI, and ApoB levels than the subjects with CT or CC genotype. Serum lipid parameters were also correlated with several environmental factors in both ethnic groups. The differences in the association of KLF14 rs4731702 SNP and serum lipid levels between the two ethnic groups might partly result from different gene-environmental interactions.

APOE4-specific Changes in Aβ Accumulation in a New Transgenic Mouse Model of Alzheimer Disease

APOE4 is the greatest risk factor for Alzheimer disease (AD) and synergistic effects with amyloid-β peptide (Aβ) suggest interactions among apoE isoforms and different forms of Aβ accumulation. However, it remains unclear how the APOE genotype affects plaque morphology, intraneuronal Aβ, soluble Aβ42, and oligomeric Aβ (oAβ), particularly in vivo. As the introduction of human APOE significantly delays amyloid deposition in transgenic mice expressing familial AD (FAD) mutations (FAD-Tg), 5xFAD-Tg mice, which exhibit amyloid deposition by age 2 months, were crossed with apoE-targeted replacement mice to produce the new EFAD-Tg mice. Compared with 5xFAD mice, Aβ deposition was delayed by ∼4 months in the EFAD mice, allowing detection of early changes in Aβ accumulation from 2-6 months. Although plaque deposition is generally greater in E4FAD mice, E2/E3FAD mice have significantly more diffuse and E4FAD more compact plaques. As a first report in FAD-Tg mice, the APOE genotypes had no effect on intraneuronal Aβ accumulation in EFAD mice. In E4FAD mice, total apoE levels were lower and total Aβ levels higher than in E2FAD and E3FAD mice. Profiles from sequential three-step extractions (TBS, detergent, and formic acid) demonstrated that the lower level of total apoE4 is reflected only in the detergent-soluble fraction, indicating that less apoE4 is lipoprotein-associated, and perhaps less lipidated, compared with apoE2 and apoE3. Soluble Aβ42 and oAβ levels were highest in E4FAD mice, although soluble apoE2, apoE3, and apoE4 levels were comparable, suggesting that the differences in soluble Aβ42 and oAβ result from functional differences among the apoE isoforms. Thus, APOE differentially regulates multiple aspects of Aβ accumulation.

Abstract 18904: High-denisty Lipoprotein Distribution in Obesity Favors Apolipoprotein E and C-III-containing Subfractions Associated with Risk for Future Coronary Heart Disease

Human high-density lipoprotein (HDL) particles are highly heterogeneous in composition. Both the plasma concentration of HDL with apoC-III and the concentration of apoE in HDL predict higher incidence of coronary heart disease (CHD). Little is known about the concentration of HDL apoA-I associated with apoE or apoC-III, whether apoE and apoC-III are present in smaller or larger cholesterol ester-rich HDL, and whether the distribution is affected in obesity. We studied 20 normal weight subjects (BMI 23-25) and 20 obese subjects (BMI 30-35) matched by age (mean age, 51 years). Sixteen distinct HDL subpopulations were separated from plasma samples by first using anti-apoAI, anti-apoE and anti-apoC-III immunoaffinity chromatography in sequence followed by size separation using nondenaturing electrophoresis. The mean HDL-cholesterol and plasma apoA-I concentrations in the normal weight group were 65 and 179mg/dL respectively, compared to 50 and 170mg/dL in the obese group. Mean apoA-I concentrations of HDL fractions without apoE or apoC-III was 160mg/dL in the normal weight group, compared to 136mg/dL in the obese; with apoE only 9 and 12mg/dL respectively; with apoC-III only 7.4 and 14.7 mg/dL; and with both apoE and apoC-III 2.6 and 7.5mg/dL (p&lt;0.01 for a difference in apoA-I concentration and distribution across HDL types). All told, about 10% of HDL apoA-I in normal weight subjects contained apoE, apoC-III or both, compared to 20% in obese subjects. The concentrations of apoE and apoC-III in HDL in the obese were about double that of the normal weight group (p&lt;0.01). In the obese group, the high concentration of HDL with apoE was distributed to small HDL. More so, obese had a higher percent of large HDL containing apoC-III and no apoE. In conclusion, despite similar plasma total apoA-I levels in obese and normal weight groups, the obese had higher concentrations of HDL containing apoE or apoC-III, subfractions which are associated with CHD, whereas the normal weight group had higher concentration of HDL without apoE or apoC-III, a subtraction with protective association against CHD. Mechanistically, the increased presence of apoC-III in large size HDL and apoE in small size HDL in obese may indicate a reduced capacity of HDL for RCT.

15N-labeled full-length apolipoprotein E4 as an internal standard for mass spectrometry quantification of apolipoprotein E isoforms.

Apolipoprotein E isoforms (apoE2, apoE3, and apoE4) affect the likelihood of developing Alzheimer's disease (AD), with the apoE4 isoform being a major risk factor. However, the underlying mechanism remains to be determined. ApoE isoforms vary by a single amino acid change, and it is a challenge to distinguish them on the protein level. We developed a mass spectrometry-based quantitative method utilizing (15)N-labeled full-length apoE4 ((15)N-apoE4) as an internal standard to quantify concentrations of the specific apoE4 isoform and total apoE. The measurements were performed on control and severe AD samples from human postmortem brain in a single experimental run with a single internal standard, (15)N-apoE4. By subtracting apoE4 from total apoE, the concentration of apoE2 or apoE3 for individuals possessing ε2/ε4 or ε3/ε4 alleles can be assessed. Moreover, using the full-length (15)N-apoE4 standard for the set of samples with pure ε2/ε2, ε3/ε3, or ε4/ε4 genotypes makes possible comparison of changes that occur in individual apoE2, apoE3, or apoE4 isoforms, respectively. Overall, using this method, it is possible to study the differences between apoE isoform functions on the protein level and therefore to understand the underlying biological mechanism by which apoE alters AD susceptibility.

Low osteocalcin/collagen type I bone gene expression ratio is associated with hip fragility fractures

IntroductionOsteocalcin (OC) is the most abundant non-collagenous bone protein and is determinant for bone mineralization.We aimed to compare OC bone expression and serum factors related to its carboxylation in hip fragility fracture and osteoarthritis patients. We also aimed to identify which of these factors were associated with worse mechanical behavior and with the hip fracture event. MethodsIn this case-control study, fragility fracture patients submitted to hip replacement surgery were evaluated and compared to a group of osteoarthritis patients submitted to the same procedure. Fasting blood samples were collected to assess apolipoproteinE (apoE) levels, total OC and undercarboxylated osteocalcin (ucOC), vitamin K, LDL cholesterol, triglycerides and bone turnover markers. The frequency of the apoε4 isoform was determined.Femoral epiphyses were collected and trabecular bone cylinders drilled in order to perform compression mechanical tests. Gene expression of bone matrix components was assessed by quantitative RT-PCR analysis. Results64 patients, 25 submitted to hip replacement surgery due to fragility fracture and 39 due to osteoarthritis, were evaluated. Bone OC/collagen expression (OC/COL1A1) ratio was significantly lower in hip fracture compared to osteoarthritis patients (p<0.017) adjusted for age, gender and body mass index. Moreover, OC/COL1A1 expression ratio was associated with the hip fracture event (OR ~0; p=0.003) independently of the group assigned, or the clinical characteristics. Apoε4 isoform was more frequent in the hip fracture group (p=0.029). ucOC levels were higher in the fracture group although not significantly (p=0.058). No differences were found regarding total OC (p=0.602), apoE (p=0.467) and Vitamin K (p=0.371).In hip fracture patients, multivariate analysis, adjusted for clinical characteristics, serum factors related to OC metabolism and gene expression of bone matrix proteins showed that low OC/COL1A1 expression ratio was significantly associated with worse trabecular strength (β=0.607; p=0.013) and stiffness (β=0.693; p=0.003). No association was found between ucOC and bone mechanics. Moreover, in osteoarthritis patients, the multivariate analysis revealed that serum total OC was negatively associated with strength (β=−0.411; p=0.030) and stiffness (β=−0.487; p=0.009). ConclusionWe demonstrated that low bone OC/COL1A1 expression ratio was an independent predictor of worse trabecular mechanical behavior and of the hip fracture event. These findings suggest that in hip fracture patients the imbalance of bone OC/COL1A1 expression ratio reflects disturbances in osteoblast activity leading to bone fragility.

Total ApoE and ApoE4 Isoform Assays in an Alzheimer's Disease Case-control Study by Targeted Mass Spectrometry (n = 669): A Pilot Assay for Methionine-containing Proteotypic Peptides

Allelic polymorphism of the apolipoprotein E (ApoE) gene (ApoE ε2, ApoE ε3 and ApoE ε4 alleles) gives rise to three protein isoforms (ApoE2, ApoE3 and ApoE4) that differ by 1 or 2 amino acids. Inheritance of the ApoE ε4 allele is a risk factor for developing Alzheimer's disease (AD). The potential diagnostic value of ApoE protein levels in biological fluids (i.e. cerebrospinal fluid, plasma and serum) for distinguishing between AD patients and healthy elderly subjects is subject to great controversy. Although a recent study reported subnormal total ApoE and ApoE4 levels in the plasma of AD patients, other studies have found normal or even elevated protein levels (versus controls). Because all previously reported assays were based on immunoenzymatic techniques, we decided to develop an orthogonal assay based on targeted mass spectrometry by tracking (i) a proteotypic peptide common to all ApoE isoforms and (ii) a peptide that is specific for the ε4 allele. After trypsin digestion, the ApoE4-specific peptide contains an oxidation-prone methionine residue. The endogenous methionine oxidation level was evaluated in a small cohort (n=68) of heterozygous ε3ε4 carriers containing both healthy controls and AD patients. As expected, the proportion of oxidized residues varied from 0 to 10%, with an average of 5%. We therefore developed a standardized strategy for the unbiased, absolute quantification of ApoE4, based on performic acid oxidization of methionine. Once the sample workflow had been thoroughly validated, it was applied to the concomitant quantification of total ApoE and ApoE4 isoform in a large case-control study (n=669). The final measurements were consistent with most previously reported ApoE concentration values and confirm the influence of the different alleles on the protein expression level. Our results illustrate (i) the reliability of selected reaction monitoring-based assays and (ii) the value of the oxidization step for unbiased monitoring of methionine-containing proteotypic peptides. Furthermore, a statistical analysis indicated that neither total ApoE and ApoE4 levels nor the ApoE/ApoE4 ratio correlated with the diagnosis of AD. These findings reinforce the conclusions of previous studies in which plasma ApoE levels had no obvious clinical significance.

(9) Evaluation of genotype scoring criteria for familial hypercholesterolaemia (FH) in wales

s / Atherosclerosis 223 (2012) 527–535 530 Methods: ApoE and glycated apoE distributions in different lipoproteins in 32 (18 men and 14 women) healthy volunteers were determined. Results: Total apoE concentration (mean SEM) was 48.2 2.4 mg/l. Of this 13.3 2.5 mg/l (27.6%) was in VLDL, 10.6 2.2 mg/l (22.0%) in LDL, 14.4 1.2 mg/l (29.9%) in HDL and 9.9 2.0 mg/l (20.5%) in the density range >1.21 g/ml. ApoE concentration in VLDL was strongly correlated with VLDL-apoB and VLDL-TG. There was no significant difference in total apoE between men and women. However, in men VLDL-apoE was significantly higher (15.6 1.4 mg/l vs. 10.3 1.4 mg/l, p 1.21 g/ml were glycated. Conclusions: The apoE concentration and lipoproteins distribution are influenced by age and gender. VLDL and LDL apoE are more susceptible to glycation in vivo.

Serum lipid profile in psoriatic patients: correlation between vascular adhesion protein 1 and lipoprotein (a)

Psoriasis is a chronic inflammatory skin disease characterized by excessive cellular replication. Apolipoproteins are genetically determined molecule whose role has been implied in cardiovascular pathology. Vascular adhesion protein-1 (VAP-1) is an adhesion molecule with an enzymatic activity that partakes in the migration process of lymphocytes into sites of inflammation. Our purpose was to evaluate the plasma lipid profiles, apolipoproteins (A1, B) and Lp (a) and VAP-1 in order to compare the lipid profile in psoriatic patients with non-affected persons and correlation between VAP-1 and Lp (a). We determined serum concentrations of lipids, lipoproteins , apolipoproteins and VAP-1 in 90 patients with psoriasis and 90 age matched controls. Serum Lp (a), apo A1 and apo B were measured by immunoprecipitation assays, and the lipids and lipoproteins were measured by enzymatic methods.The VAP-1 were measured by ELISA method. The mean levels of total cholesterol, LDL, apo B and VAP-1 in patients with psoriasis were found to be significantly higher than those of healthy subjects (P<0.05. In psoriatic patients, elevation of VAP-1 correlated with elevation of Lp (a) (p = 0.025). This study shows that high serum lipid level and VAP-1, is significantly more common in psoriasis. This fact may be responsible for higher prevalence of cardiovascular accident in psoriatic patients.

The Polymorphism of the ATP-Binding Cassette Transporter 1 Gene Modulates Alzheimer Disease Risk in Chinese Han Ethnic Population

Recent studies highlight a potential role of cholesterol metabolic disturbance in the pathophysiology of Alzheimer disease (AD). The adenosine triphosphate (ATP)-binding cassette transporter 1 (ABCA1) gene resides within proximity of linkage peaks on chromosome 9q influence AD and plays a key role in cellular cholesterol efflux in the brain. We studied the role of R219K and V825I polymorphisms of ABCA1 in modulating the risk of AD in 321 AD patients and 349 comparisons of Chinese Han. Genotyping of R219K and V825I were performed by PCR-restriction fragment length polymorphism analysis. The genotype distribution of R219K was different with more RK in total AD group (χ(2) = 8.705, df = 2, p = 0.013), late-onset AD (LOAD) group (χ(2) = 10.636, df = 2, p = 0.005), APOE non-ε4ε4 group (χ(2) = 9.900, df = 2, p = 0.007), and female AD group (χ(2) = 8.369, df = 2, p = 0.015). Logistic regression manifested the risk of AD increased in RK carriers in total AD group (Wald = 6.102, df = 1, p = 0.014, odds ratio [OR]: 1.546, 95% confidence interval [95% CI]: 1.094-2.185), LOAD group (Wald = 7.746, df = 1, p = 0.005, OR: 1.921, 95% CI: 1.213-3.041), and APOE non-ε4ε4 group (Wald = 6.399, df = 1, p = 0.011, OR: 1.586, 95% CI: 1.109-2.266). K allele (RK + KK) also increased the risk of AD compared with RR allele in LOAD group (Wald = 4.750, df = 1, p = 0.029, OR: 1.619, 95% CI: 1.050-2.497). However, no discrepancy was found in V825I. In R219K, age at onset (AAO) was significantly lower by 4.9 years on average in patients of KK genotype than those of RK in APOE ε4 carrying group and higher by 5.5 years in patients of KK genotype than those of RR in APOE ε4 noncarrying group. In V825I, AAO was diseased by 4.3 years in II genotype compared with VV genotype in APOE ε4 noncarrying group and 3.4 years in APOE ε4ε4 noncarrying group. The results indicated that the RK genotype or K allele (RK + KK) of R219K may relate to the development of AD in the east of China.

P1‐011: Donepezil treatment's late effects on cytokines release from lymphocytes of Alzheimer's disease patients

Imaging, Biomarkers and Lifestyle (AIBL) Longitudinal Study of Ageing using commercial Luminex 96 well assay kits. Total APOE plasma levels were then compared between non-memory complainers (NMC), subjective memory complainers (SMC), mild cognitively impaired (MCI) individuals and AD patients. The data was further compared against other collected demographics including but not limited to cerebral amyloid load as measured by positron emission tomography (PET), APOE genotype and neuropsychological scores. Results: Total protein APOE levels were significantly lower in the AD cohort, as compared to both the NMC and SMC groups. No significant correlation was found, at this time, between APOE levels and cerebral amyloid beta load, however, further analysis will determine the relationship between plasma APOE and plasma Ab levels. Significant differences in plasma APOE levels were observed between different genotypes as well. In general, those with the E4/E4 genotype have the lowest levels of plasma APOE. Conclusions: APOE shows great promise as an AD biomarker for the future development of an AD diagnostic assay with its altered protein levels between AD and control participant groups. Completed measurements of baseline plasma samples from the same individuals will add great value to this study, by analysing the changes in plasma APOE over time. The significance of these findings can be determined further as the AIBL longitudinal study of ageing continues.

O2‐06‐05: A voxel‐based morphometry study of volumetric MRI in familial Alzheimer's disease

DIAN (Dominantly Inherited Alzheimer's Network) is an international longitudinal study of autosomal dominant Alzheimer's disease that involves serial clinical, imaging and biomarker studies of individuals at risk of disease and those already mildly affected. Understanding the patterns of atrophy associated with the disease will be important for studies and trials tracking atrophy progression in these cohorts. 158 participants from the DIAN cohort were included of whom 55 were non carriers (NC); 59 were asymptomatic carriers (aMut+) with a Clinical Dementia Rating (CDR) of 0; and 44 were symptomatic carriers (sMut+) with CDR >0. Voxel based morphometry (VBM) of baseline MR imaging was used to investigate differences in grey matter (GM) and white matter (WM) between the different groups. Tissue segmentation and spatial normalization of volumetric T1-weighted images were performed using the VBM8 toolbox of SPM8. One participant was excluded due to severe WM hyperintensities. Images were smoothed using a 6mm full-width-half-maximum Gaussian kernel. Statistical parametric maps were generated of the GM and WM differences between groups, controlling for total intracranial volume (TIV), gender, acquisition site, and APOE genotype. An interaction term between group and the expected age of onset (current age - parental age of onset) was included. Significant clusters (P <0.05 Family-Wise Error corrected) in the GM were observed between groups in the thalamus, precuneus, putamen, and amygdala. Most clusters were primarily driven by differences between the sMut+ and NC group (see Figure). No significant clusters were observed between the aMut+ and NC groups. There were also clusters in the parahippocampal/hippocampal regions. WM differences between groups were observed in the fornix superior to the thalamus, the cingulum inferiorly adjacent to the hippocampus, the splenium adjacent to the cingulate and areas adjacent to the precuneus. Symptomatic subjects show widespread differences in GM volume including deep grey structures (e.g. thalamus and putamen) and the precuneus; notable white matter changes included the fornix and the cingulum. The deep grey changes are of interest as PIB PET findings suggest early amyloid deposition in these structures.

IC‐P‐020: A voxel‐based morphometry study of volumetric MRI in familial Alzheimer's disease

Background DIAN (Dominantly Inherited Alzheimer’s Network) is an international longitudinal study of autosomal dominant Alzheimer’s disease that involves serial clinical, imaging and biomarker studies of individuals at risk of disease and those already mildly affected. Understanding the patterns of atrophy associated with the disease will be important for studies and trials tracking atrophy progression in these cohorts. Methods 158 participants from the DIAN cohort were included of whom 55 were non carriers (NC); 59 were asymptomatic carriers (aMut+) with a Clinical Dementia Rating (CDR) of 0; and 44 were symptomatic carriers (sMut+) with CDR \textgreater0. Voxel based morphometry (VBM) of baseline MR imaging was used to investigate differences in grey matter (GM) and white matter (WM) between the different groups. Tissue segmentation and spatial normalization of volumetric T1-weighted images were performed using the VBM8 toolbox of SPM8. One participant was excluded due to severe WM hyperintensities. Images were smoothed using a 6mm full-width-half-maximum Gaussian kernel. Statistical parametric maps were generated of the GM and WM differences between groups, controlling for total intracranial volume (TIV), gender, acquisition site, and APOE genotype. An interaction term between group and the expected age of onset (current age - parental age of onset) was included. Results Significant clusters (P \textless0.05 Family-Wise Error corrected) in the GM were observed between groups in the thalamus, precuneus, putamen, and amygdala. Most clusters were primarily driven by differences between the sMut+ and NC group (see Figure). No significant clusters were observed between the aMut+ and NC groups. There were also clusters in the parahippocampal/hippocampal regions. WM differences between groups were observed in the fornix superior to the thalamus, the cingulum inferiorly adjacent to the hippocampus, the splenium adjacent to the cingulate and areas adjacent to the precuneus. Conclusions Symptomatic subjects show widespread differences in GM volume including deep grey structures (e.g. thalamus and putamen) and the precuneus; notable white matter changes included the fornix and the cingulum. The deep grey changes are of interest as PIB PET findings suggest early amyloid deposition in these structures.

Abstract 319: Dalcetrapib-Mediated Modulation of Cholesteryl Ester Transfer Protein Activity Increases HDL-Cholesterol, Apolipoprotein A-I Levels and Cholesterol Efflux Capacity in Chow-Fed Rabbits

Introduction: A potential approach to reduce CV risk is to increase HDL-C levels. This could be achieved by reducing cholesteryl ester transfer protein (CETP) activity. Dalcetrapib, which modulates CETP activity by changing its conformation and raises HDL-C without inhibiting CETP-induced pre-β-HDL formation in humans, was shown to decrease progression of atherosclerosis in rabbits. Hypothesis: Investigate the modifications of HDL particle size distribution and cholesterol efflux capacity of serum produced by dalcetrapib in normocholesterolemic rabbits. Methods: New Zealand white rabbits were treated with dalcetrapib (300 mg/kg as food admix) or placebo for 14 days. We evaluated CETP conformation and mass by ELISAs (including antibodies sensitive to conformational change), CETP activity by fluorescent lipid transfer, lipid profile and apoA-I distribution in HDL subclasses by 2D-non denaturing gradient gels (2D-NDGGE). Cholesterol efflux capacity of rabbit sera was determined after loading cells with 3 H-free cholesterol, using HepG2 hepatocytes to measure SR-BI-dependent efflux and by inducing ABCA1 or ABCG1 expression in BHK cells. Results: Dalcetrapib modified the conformation of rabbit CETP in vitro and in vivo and, after 14 days, this was associated with increased CETP mass (+50%, p&lt;0.001) and reduced CETP activity (-86%, p&lt;0.001). Total cholesterol was increased with dalcetrapib (+178%, p&lt;0.001), due to a higher HDL-C level. In contrast, dalcetrapib reduced LDL-C and triglycerides by 41% (p&lt;0.01) and 48% (p&lt;0.001). Serum analysis by 2D-NDGGE showed that total rabbit apoA-I was increased 1.7- fold in animals treated with dalcetrapib. This was associated with an increase in large HDL but also in small α-migrating HDL with pre-β-HDL size. Cholesterol efflux assays showed that ABCA1-, ABCG1- and SR-BI-dependent efflux were all increased in dalcetrapib-treated rabbits (+24%, p=0.038; +21%, p=0.021; +44%, p&lt;0.001). Conclusion: Modulation of CETP activity and conformation by dalcetrapib increases HDL-C and apoA-I levels and affects apoA-I distribution in HDL subclasses. These changes are associated with increased cholesterol efflux capacity, suggesting that HDL functionality is preserved in dalcetrapib-treated chow-fed rabbits.

Low serum apolipoprotein A1/B ratio is associated with proliferative diabetic retinopathy in type 2 diabetes

The association between lipids and diabetic retinopathy (DR) remains unclear. Only a few studies have reported the association between proliferative diabetic retinopathy (PDR) and the serum concentrations of apolipoprotein A1 (apoA1), apolipoprotein B (apoB) and apolipoprotein E (apoE). So we investigated the lipid profile in type 2 diabetic patients of long duration with very mild nonproliferative diabetic retinopathy (NPDR) or PDR. Serum samples were obtained from 25 type 2 diabetic patients with very mild NPDR and 25 type 2 diabetic patients with PDR, and the two groups were matched by diabetes duration and glycosylated hemoglobin (HbA(1c)) levels. The levels of total cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apoA1, apoB, and apoE were measured by enzymatic colorimetric, surfactant, and immunotubidimetric method. Compared with PDR subjects, very mild NPDR subjects were characterized by increased HDL cholesterol (P = 0.0433) and apoA1 (P = 0.0290) levels, higher HDL cholesterol/LDL cholesterol (P = 0.0377) and apoA1/apoB (P = 0.0061) ratio in serum. There were significant associations between the decreased apoA1 and low apoA1/apoB ratio in serum and PDR. Even after adjustment for age, decreased apoA1 level (P = 0.0304) and low apoA1/apoB ratio (P = 0.0218) in serum were significantly associated with PDR in type 2 diabetic patients of over 15years' duration. Low apolipoprotein A1/apolipoprotein B ratio in serum was associated with PDR in type 2 diabetic patients of long duration.

The origin and metabolism of a nascent pre-β high density lipoprotein involved in cellular cholesterol efflux.

The pre-β HDL fraction constitutes a heterogeneous population of discoid nascent HDL particles. They transport from 1 to 25 % of total human plasma apo A-I. Pre-β HDL particles are generated de novo by interaction between ABCA1 transporters and monomolecular lipid-free apo A-I. Most probably, the binding of apo A-I to ABCA1 initiates the generation of the phospholipid-apo A-I complex which induces free cholesterol efflux. The lipid-poor nascent pre-β HDL particle associates with more lipids through exposure to the ABCG1 transporter and apo M. The maturation of pre-β HDL into the spherical α-HDL containing apo A-I is mediated by LCAT, which esterifies free cholesterol and thereby forms a hydrophobic core of the lipoprotein particle. LCAT is also a key factor in promoting the formation of the HDL particle containing apo A-I and apo A-II by fusion of the spherical α-HDL containing apo A-I and the nascent discoid HDL containing apo A-II. The plasma remodelling of mature HDL particles by lipid transfer proteins and hepatic lipase causes the dissociation of lipid-free/lipid-poor apo A-I, which can either interact with ABCA1 transporters and be incorporated back into pre-existing HDL particles, or eventually be catabolized in the kidney. The formation of pre-β HDL and the cycling of apo A-I between the pre-β and α-HDL particles are thought to be crucial mechanisms of reverse cholesterol transport and the expression of ABCA1 in macrophages may play a main role in the protection against atherosclerosis.

Plasma apolipoprotein C-III metabolism in patients with chronic kidney disease

Moderate chronic kidney disease (CKD) (defined by an estimated glomerular filtration rate of 30-60 ml/min) is associated with mild hypertriglyceridemia related to delayed catabolism of triglyceride-rich lipoprotein particles. Altered apolipoprotein C-III (apoC-III) metabolism may contribute to dyslipidemia in CKD. To further characterize the dyslipidemia of CKD, we investigated the kinetics of plasma apoC-III in 7 nonobese, nondiabetic, non-nephrotic CKD subjects and 7 age- and sex-matched healthy controls, using deuterated leucine ([5, 5, 5, ²H₃]leucine), gas chromatography-mass spectrometry, and multicompartmental modeling. Compared with controls, CKD subjects had higher concentrations of plasma and VLDL triglycerides and plasma and VLDL apoC-III (P < 0.05). The increased plasma apoC-III concentration was associated with a decreased apoC-III fractional catabolic rate (FCR) (1.21 ± 0.15 vs. 0.74 ± 0.12 pools/day, P = 0.03). There were no differences between apoC-III production rates of controls and those of CKD subjects. In CKD subjects, plasma apoC-III concentration was significantly and negatively correlated with apoC-III FCR (r = -0.749, P = 0.05) but not with apoC-III production rate. Plasma apoC-III concentration was positively correlated with plasma and VLDL triglycerides and VLDL apoB concentrations and negatively correlated with VLDL apoB FCR (P < 0.05 for all). ApoC-III FCR was negatively correlated with plasma and VLDL triglycerides and VLDL apoB concentration and positively correlated with VLDL apoB FCR (P < 0.05 for all). Altered plasma apoC-III metabolism is a feature of dyslipidemia in moderate CKD. Modification of apoC-III catabolism may be an important therapeutic target for reducing cardiovascular disease risk in moderate CKD.

Plasma apolipoprotein E and Alzheimer disease risk

There is mounting evidence for the contribution of apoE to the pathophysiology of Alzheimer disease (AD). Studies also indicate that plasma apoE levels may reflect disease status, suggesting that apoE is a potential AD biomarker. However, while some studies of apoE levels in plasma have presented correlations with AD pathology, others have not. Thus, there is a lack of consensus as to the suitability of plasma apoE as an AD biomarker. The major objective of this cross-sectional study was to investigate total plasma apoE as well as levels of the apoE4 form in a large, highly characterized cohort which included both healthy controls and participants with early-stage AD. Total apoE and apoE4 were measured in 1,079 individuals drawn from the highly characterized Australian Imaging, Biomarkers and Lifestyle (AIBL) study. Total and isoform-specific plasma apoE levels were then compared with cerebral Aβ load, as assessed by PET using Pittsburgh compound B (PiB). Total apoE and apoE4 levels were found to be significantly lower in patients with AD in the entire cohort, and decrease with Aβ load in the PiB-PET subset. ApoE levels were significantly lower among ε4 homozygous individuals. In APOE ε3/ε4 heterozygote carriers, apoE4 levels decrease, indicating that apoE3 levels increase with disease. Analysis of cross-sectional data from the AIBL study indicates that plasma apoE levels are altered in AD and correlate with AD pathology level. The significance of these findings will be determined in the AIBL longitudinal study of aging.

Lipid profile, apolipoprotein A-I and oxidative stress in professional footballers, sedentary individuals, and their relatives

To evaluate whether lipid profile (LP), apolipoprotein A-1 (apo A-I) and malondialdehyde (MDA) have any relationship with physical exercise by comparing the groups of footballers (FG) with sedentary individuals (CG) and their relatives (RFG and RCG). Twenty individuals from FG and CG, 60 from RFG, and 57 from RCG were studied. FG showed lower levels of total cholesterol (119.5 ± 37.9 mg/dL), LDL-cholesterol fraction (53.6 ± 30.3), apo A-I (116.7 ± 11.9), and higher level of HDL-cholesterol fraction (HDLc) (49.7 ± 8.5) compared to RFG (148.3 ± 36.9, P = 0.02; 82.4 ± 37.7, P < 0.01; 124.6 ± 10.2, P = 0.03; and 42.7 ± 7.7, P < 0.01; respectively). Moreover, FG had reduced levels of MDA (101.0 ± 77.0 ng/mL) compared to CG (290.0 ± 341.0, P = 0.03) and RFG (209.9 ± 197.5, P = 0.04). These results suggest an association between physical exercise and lower levels of MDA in FG. Physical activity seems to promote beneficial effects on the LP regardless of the genetic influence considering HDLc levels.