Noninvasive risk stratification of intraductal papillary mucinous neoplasia with malignant potential by serum apolipoprotein-A2-isoforms.

Intraductal papillary mucinous neoplasms (IPMNs) are premalignant lesions of pancreatic cancer. An accurate serum biomarker, which allows earlier identification of asymptomatic individuals with high-risk for developing cancer, is of urgent need. Apolipoprotein A2-isoforms (apoA2-i) have previously been identified as biomarkers in pancreatic cancer. This study investigates a potential clinical application of the serum apoA2-i for risk stratification of IPMN and associated cancer. The concentrations of apoA2-i were retrospectively determined in 523 patient sera specimen, composed of 305 IPMNs with preinvasive lesions with different grades of dysplasia and invasive cancer, 140 pancreatic ductal adenocarcinoma, 78 with other cystic lesions and healthy controls cohorts, using an apoA2-i enzyme-linked immunosorbent assay kit. The diagnostic performance of serum apoA2-i was assessed and compared to routine clinical marker CA 19-9. ApoA2-i levels were significantly reduced in all IPMN samples regardless of stage compared to healthy controls. Receiver operating characteristic curve analysis of IPMNs with high-grade dysplasia and IPMN with associated carcinoma revealed the area under curve (AUC) of 0.91 and >0.94, respectively. The respective sensitivities were 70% and 83% with a specificity of 95%, and significantly higher than the gold standard biomarker CA 19-9. AUC values of apoA2-i for detecting IPMN-associated carcinoma of colloid and ductal subtypes were 0.990 and 0.885, respectively. ApoA2-i has the potential to early detect the risk of malignancy of patients with IPMN. The serological apoA2-i test in combination with imaging modalities could help improve the diagnosis of IPMN malignancy. Further validation in larger and independent international cohort studies is needed.

Spectrum of Apolipoprotein AI and Apolipoprotein AII Proteoforms and Their Associations With Indices of Cardiometabolic Health: The CARDIA Study.

Background ApoAI (apolipoproteins AI) and apoAII (apolipoprotein AII) are structural and functional proteins of high-density lipoproteins (HDL) which undergo post-translational modifications at specific residues, creating distinct proteoforms. While specific post-translational modifications have been reported to alter apolipoprotein function, the full spectrum of apoAI and apoAII proteoforms and their associations with cardiometabolic phenotype remains unknown. Herein, we comprehensively characterize apoAI and apoAII proteoforms detectable in serum and their post-translational modifications and quantify their associations with cardiometabolic health indices. Methods and Results Using top-down proteomics (mass-spectrometric analysis of intact proteins), we analyzed paired serum samples from 150 CARDIA (Coronary Artery Risk Development in Young Adults) study participants from year 20 and 25 exams. Measuring 15 apoAI and 9 apoAII proteoforms, 6 of which carried novel post-translational modifications, we quantified associations between percent proteoform abundance and key cardiometabolic indices. Canonical (unmodified) apoAI had inverse associations with HDL cholesterol and HDL-cholesterol efflux, and positive associations with obesity indices (body mass index, waist circumference), and triglycerides, whereas glycated apoAI showed positive associations with serum glucose and diabetes mellitus. Fatty-acid‒modified ApoAI proteoforms had positive associations with HDL cholesterol and efflux, and inverse associations with obesity indices and triglycerides. Truncated and dimerized proteoforms of apoAII were associated with HDL cholesterol (positively) and obesity indices (inversely). Several proteoforms had no significant associations with phenotype. Conclusions Associations between apoAI and AII and cardiometabolic indices are proteoform-specific. These results provide "proof-of-concept" that precise chemical characterization of human apolipoproteins will yield improved insights into the complex pathways through which proteins signify and mediate health and disease.

Metabolomic signatures associated with depression and predictors of antidepressant response in humans: A CAN-BIND-1 report.

One of the biggest challenges in treating depression is the heterogeneous and qualitative nature of its clinical presentations. This highlights the need to find quantitative molecular markers to tailor existing treatment strategies to the individual's biological system. In this study, high-resolution metabolic phenotyping of urine and plasma samples from the CAN-BIND study collected before treatment with two common pharmacological strategies, escitalopram and aripiprazole, was performed. Here we show that a panel of LDL and HDL subfractions were negatively correlated with depression in males. For treatment response, lower baseline concentrations of apolipoprotein A1 and HDL were predictive of escitalopram response in males, while higher baseline concentrations of apolipoprotein A2, HDL and VLDL subfractions were predictive of aripiprazole response in females. These findings support the potential of metabolomics in precision medicine and the possibility of identifying personalized interventions for depression.

Apolipoprotein A2 Isoforms in Relation to the Risk of Myocardial Infarction: A Nested Case-Control Analysis in the JPHC Study.

AIM: The fact that low concentrations of high-density lipoprotein cholesterol are associated with the risk of cardiovascular disease is well known, but high-density lipoprotein metabolism has not been fully understood. Apolipoprotein A2 (ApoA2) is the second-most dominant apolipoprotein of high-density lipoprotein. We tested the hypothesis that ApoA2 isoforms are inversely associated with myocardial infarction. METHODS: We measured the plasma levels of three ApoA2 isoforms (ApoA2-ATQ/ATQ, ApoA2-ATQ/AT, ApoA2-AT/AT) in nested case-control study samples of 1:2 from the Japan Public Health-Center-based Study (JPHC Study): 106 myocardial infarction incidence cases and 212 controls. RESULTS: ApoA2-AT/AT was inversely associated with risk of myocardial infarction, in a matched model (OR, 2.78; 95% CI, 1.26-6.09 for lowest compared with the highest quartile), but its association was attenuated after adjustment for smoking only (OR=2.13; 95% CI, 0.91-4.97) or drinking only (OR=2.11; 0.91-4.89), and the multivariable OR was 1.20 (95% CI, 0.41-3.57). Neither ApoA2-ATQ/ATQ nor ApoA2-ATQ/AT was associated with the risk of myocardial infarction. CONCLUSIONS: Our nested case-control study did not show a significant association of ApoA2 isoforms with a risk of myocardial infarction.

Neuroprotective associations of apolipoproteins A-I and A-II with neurofilament levels in early multiple sclerosis.

BACKGROUND: The role of cholesterol homeostasis in neuroaxonal injury in multiple sclerosis is not known. OBJECTIVE: The objective of the study is to investigate the associations of cerebrospinal fluid (CSF) and serum neurofilament light chain levels (CSF-NfL and sNfL, respectively), which are biomarkers of neuroaxonal injury, with cholesterol biomarkers at the clinical onset of multiple sclerosis. METHODS: sNfL, serum cholesterol profile (total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol), serum apolipoprotein (Apo) levels (ApoA-I, ApoA-II, ApoB, and ApoE), and albumin quotient were obtained for 133 patients (63% female, age: 29.9 ± 8.0 years) during the first demyelinating event. CSF-NfL was available for 103 (77%) patients. RESULTS: CSF-NfL and sNfL were negatively associated with serum ApoA-II (P = .005, P < .001) and positively associated with albumin quotient (P < .001, P < .0001). In addition, higher CSF-NfL was associated with lower serum ApoA-I (P = .009) levels and higher sNfL was associated with lower high-density lipoprotein cholesterol (P = .010). In stepwise regression, age (P = .045), serum ApoA-II (P = .022), and albumin quotient (P < .001) were associated with CSF-NfL; albumin quotient (P = .002) and ApoA-II (P = .001) were associated with sNfL. Path analysis identified parallel pathways from ApoA-II (P = .009) and albumin quotient (P < .001) to the sNfL outcome that were mediated by CSF-NfL (P < .001). The associations of CSF-NfL with ApoA-I (P = .014) and ApoA-II (P = .015) and sNfL with ApoA-II (P < .001) remained significant after adjusting for number of contrast-enhancing lesions and T2 lesion volume. CONCLUSION: Lower serum ApoA-II and ApoA-I levels are associated with greater neuroaxonal injury as measured by CSF-NfL.

Omega-3 Fatty Acids Effects on Inflammatory Biomarkers and Lipid Profiles among Diabetic and Cardiovascular Disease Patients: A Systematic Review and Meta-Analysis.

The purpose of this systematic review and meta-analysis was to investigate omega-3 fatty acids' influence on 12 inflammatory biomarkers-LDL, HDL, total cholesterol, TG, HbA1c, Apo AI, Apo AII, Apo B, CRP, TNF-α, glucose, and fasting blood glucose among diabetic and cardiovascular disease (CVD) patients. We searched articles in six database engines, and 16 of the 696 articles reviewed met the inclusion criteria. Among these, lipid and inflammatory biomarkers investigated commonly included total cholesterol (11 studies), LDL, and TG (10 studies each). Overall, omega-3 was associated with a significant reduction in Apo AII among diabetic patients, as compared to different controls (-8.0 mg/dL 95% CI: -12.71, -3.29, p = 0.0009), triglycerides (-44.88 mg/dL 95% CI: -82.6, -7.16, p < 0.0001), HDL (-2.27 mg/dL 95% CI: -3.72, -0.83, p = 0.002), and increased fasting blood glucose (16.14 mg/dL 95% CI: 6.25, 26.04, p = 0.001). Omega-3 also was associated with increased LDL among CVD patients (2.10 mg/dL 95% CI: 1.00, 3.20, p = 0.0002). We conclude that omega-3 fatty acids may be associated with lower inflammatory biomarkers among diabetic and cardiovascular patients. Clinicians should be aware of these potential benefits; however, it is essential to recommend that patients consult with clinicians before any omega-3 intake.

Effects of Replacing Dietary Monounsaturated Fat With Carbohydrate on HDL (High-Density Lipoprotein) Protein Metabolism and Proteome Composition in Humans.

OBJECTIVE: Clinical evidence has linked low HDL (high-density lipoprotein) cholesterol levels with high cardiovascular disease risk; however, its significance as a therapeutic target remains unestablished. We hypothesize that HDLs functional heterogeneity is comprised of metabolically distinct proteins, each on distinct HDL sizes and that are affected by diet. Approach and Results: Twelve participants were placed on 2 healthful diets high in monounsaturated fat or carbohydrate. After 4 weeks on each diet, participants completed a metabolic tracer study. HDL was isolated by Apo (apolipoprotein) A1 immunopurification and separated into 5 sizes. Tracer enrichment and metabolic rates for 8 HDL proteins-ApoA1, ApoA2, ApoC3, ApoE, ApoJ, ApoL1, ApoM, and LCAT (lecithin-cholesterol acyltransferase)-were determined by parallel reaction monitoring and compartmental modeling, respectively. Each protein had a unique, size-specific distribution that was not altered by diet. However, carbohydrate, when replacing fat, increased the fractional catabolic rate of ApoA1 and ApoA2 on alpha3 HDL; ApoE on alpha3 and alpha1 HDL; and ApoM on alpha2 HDL. Additionally, carbohydrate increased the production of ApoC3 on alpha3 HDL and ApoJ and ApoL1 on the largest alpha0 HDL. LCAT was the only protein studied that diet did not affect. Finally, global proteomics showed that diet did not alter the distribution of the HDL proteome across HDL sizes. CONCLUSIONS: This study demonstrates that HDL in humans is composed of a complex system of proteins, each with its own unique size distribution, metabolism, and diet regulation. The carbohydrate-induced hypercatabolic state of HDL proteins may represent mechanisms by which carbohydrate alters the cardioprotective properties of HDL.

High-density lipoprotein cholesterol is associated with multiple sclerosis fatigue: A fatigue-metabolism nexus?

BACKGROUND: Fatigue is a frequent symptom in multiple sclerosis (MS). The role of cholesterol and lipids in MS fatigue has not been investigated. OBJECTIVE: To investigate the associations of cholesterol biomarkers and serum neurofilament light chain (sNfL) with fatigue in relapsing-remitting MS. METHODS: This cross-sectional study included 75 relapsing-remitting MS patients (69% female, mean age ± SD: 49.6 ± 11 years and median Expanded Disability Status Scale score: 2.0). Fatigue, disability, and depression were assessed with Fatigue Severity Scale (FSS), Expanded Disability Status Scale, and the Beck Depression Index-Fast Screen, respectively. sNfL was measured using single-molecule array technology. Plasma total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and an apolipoprotein panel data were obtained. Soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular adhesion molecule-1 (sVCAM-1), chemokine (C-C motif) ligand 5 (CCL5 or RANTES), and CCL18 levels were measured to assess inflammation. RESULTS: The mean FSS was 4.27 ± 1.73, and 57% had severe fatigue status (SFS, FSS ≥ 4.0). In regression analyses adjusted for age, sex, disability, and depression, lower FSS and SFS were associated with greater HDL-C (P = .006 for FSS, and P = .016 for SFS) and lower TC to HDL-C ratio (P = .011 for FSS, and P = .009 for SFS). Apolipoprotein A-II was also associated with FSS (P = .022). sNfL, CCL5, CCL18, sICAM-1, and sVCAM-1 levels were not associated with fatigue after adjusting for disability and depression. CONCLUSIONS: TC to HDL-C ratio is associated with MS fatigue. Our results implicate a potential role for the HDL-C pathway in MS fatigue and could provide possible targets for the treatment of MS fatigue.

Decreased Antiatherogenic Protein Levels are Associated with Aneurysm Structure Alterations in MR Vessel Wall Imaging.

OBJECTIVE: Thickened intracranial aneurysm wall with atherosclerotic remodeling is a part of its degenerative scenario. Current magnetic resonance (MR)-vessel wall imaging enables the detection of atherosclerotic wall thickening as aneurysm wall enhancement. The purpose of this study was to examine the correlation between identified atherosclerotic remodeling in vessel wall imaging, and systemic atherosclerosis-related risk factors. METHODS: A total of 39 aneurysms in 38 consecutive patients scheduled to undergo microsurgical clipping or endovascular coiling of intracranial aneurysms were prospectively evaluated. All patients underwent aneurysm MR-vessel wall imaging and the presence of aneurysm wall enhancement on contrast-enhanced vessel wall imaging was evaluated. The relationship between aneurysm wall enhancement and patient demographic data, aneurysm morphology and atherosclerosis-related risk factors including blood laboratory data were assessed. RESULTS: Aneurysm wall enhancement was detected in 19 of 39 intracranial aneurysms (48.7%). The maximum diameter of the intracranial aneurysm (P < .01), apolipoprotein A2 (P < .01) and apolipoprotein C2 (P = .01) was significantly associated with the presence of aneurysm wall enhancement. In multivariate logistic regression analyses, the maximum diameter of the intracranial aneurysm (odds ratio: 1.67, 95% confidence interval: 1.17-3.05) and decreased apolipoprotein A2 (odds ratio: 0.62, 95% confidence interval: 0.34-0.97) was significantly correlated with aneurysm wall enhancement. CONCLUSIONS: Rather than atherosclerotic factors, antiatherogenic proteins reduction was associated with aneurysm wall enhancement in vessel wall imaging. To elucidate antiatherogenic factors might to help find out promoting factor of unruptured intracranial aneurysms instability.

Clinical Significance of Plasma Apolipoprotein-AII Isoforms as a Marker of Pancreatic Exocrine Disorder for Patients with Pancreatic Adenocarcinoma Undergoing Chemoradiotherapy, Paying Attention to Pancreatic Morphological Changes.

BACKGROUND: Circulating apolipoprotein-AII (apoAII-) ATQ/AT is a potential useful biomarker for early stage pancreatic ductal adenocarcinoma (PDAC), but its clinical significance in PDAC patients remains uncertain. The aim of the current study was to assess the usefulness of apoAII-ATQ/AT as a surrogate for the effect of chemoradiotherapy (CRT) and its association with pancreatic exocrine disorder, paying attention to morphological changes of the pancreas. METHODS: In the 264 PDAC patients who were enrolled in our CRT protocol, the following parameters were measured at specified time points before and after CRT: serum levels of albumin, total cholesterol, and amylase as indices of pancreatic exocrine function, serum levels of CA19-9, and the pancreatic morphology including tumor size (TS), main pancreatic duct diameter (MPDD), and pancreatic parenchymal volume excluding tumor volume (PPV) by using computed tomography (CT) images. Plasma apoAII-ATQ/AT levels were simultaneously measured with enzyme-linked immunosorbent assay in 4 healthy volunteers and the 44 PDAC patients before and after CRT. Plasma apoAII-ATQ/AT levels after CRT were analyzed according to small/large-MPDD and small/large-PPV groups based on their median values after CRT. Plasma samples after CRT were measured after incubation with human pancreatic juice (PJ) to examine the relevance between apoAII isoforms and circulating pancreatic enzymes. RESULTS: The serum levels of albumin, amylase, CA19-9, TS, MPDD, and PPV after CRT were significantly lower than those before CRT (median, before vs. after: 3.9 g/dl, 74 U/l, 180.2 U/ml, 58.1 mm, 4.0 mm, and 34.8 ml vs. 3.8, 59, 43.5, 55.6, 3.6, and 25.2). ApoAII-ATQ/AT levels (median, µg/ml) of PDAC patients before CRT were significantly lower than those in healthy volunteers: 32.9 vs. 61.2, and unexpectedly those after CRT significantly decreased: 14.7. The reduction rate of apoAII-ATQ/AT was not correlated with those of CA19-9 and TS, indicating that apoAII-ATQ/AT is not a tumor-specific marker. On the other hand, the patient group with large MPDD and small PV exhibited higher apoAII-ATQ levels than those with small MPDD and large PPV. The incubation of plasma samples after CRT with PJ did not alter apoAII-ATQ/AT and apoAII-AT levels but significantly decreased apoAII-ATQ levels, suggesting that circulating pancreatic enzymes markedly influenced apoAII-ATQ levels. CONCLUSIONS: ApoAII-ATQ/AT levels are not useful for evaluation of clinical effect of CRT for PDAC, but apoAII isoforms are very useful to assess pancreatic exocrine disorder because pancreatic atrophy and insufficient secretion of circulating pancreatic enzymes are considered likely to influence apoAII-ATQ levels.

The important role of apolipoprotein A-II in ezetimibe driven reduction of high cholesterol diet-induced atherosclerosis.

BACKGROUND AND AIMS: It has been well established that ezetimibe blocks cholesterol absorption to prevent the negative effects of a high-fat diet in atherosclerosis. However, the exact mechanism is unknown. Here we use a transgenic zebrafish, which expresses different fluorescent proteins on either endothelial cells or granulocytes and macrophages, to explore the specific mechanism of ezetimibe and its role in reducing atherosclerosis-related hypercholesteremia. METHODS: Zebrafish larvae were exposed to a control diet, high cholesterol diet (HCD) or a HCD with ezetimibe treatment. Both the control diet and high cholesterol diet were mixed with red or green fluorophore labeled cholesteryl ester to trace lipid distribution. Isobaric tags were used for relative and absolute quantification to examine protein expression profiles of zebrafish larvae in the different treatment groups. To knock down Apo A-II and investigate the role of Apo A-II in the anti-atherosclerotic function of ezetimibe, we used morpholinos to target zebrafish Apoa2 mRNA. To confirm ezetimibe regulatory role on Apo A-II expression, siRNA against HNF4, PPARα, and SREBP1 were transfected into HepG2 cells. RESULTS: The results show that ezetimibe increased the expression of Apo A-II but failed to reduce vascular lipid accumulation and macrophage recruitment induced by the HCD diet when Apo A-II was knocked down. Finally, we found that ezetimibe increased the expression of Apo A-II through HNF4 and PPARα transcriptional factors. CONCLUSIONS: Our data indicates that ezetimibe may not only prevents atherosclerosis by inhibiting cholesterol absorption in the intestine, but also by increasing the expression of Apo A-II in hepatocytes, thereby enhancing reverse cholesterol transport and removing excess cholesterol from the periphery.

CA19-9 and apolipoprotein-A2 isoforms as detection markers for pancreatic cancer: a prospective evaluation.

Recently, we identified unique processing patterns of apolipoprotein A2 (ApoA2) in patients with pancreatic cancer. Our study provides a first prospective evaluation of an ApoA2 isoform ("ApoA2-ATQ/AT"), alone and in combination with carbohydrate antigen 19-9 (CA19-9), as an early detection biomarker for pancreatic cancer. We performed ELISA measurements of CA19-9 and ApoA2-ATQ/AT in 156 patients with pancreatic cancer and 217 matched controls within the European EPIC cohort, using plasma samples collected up to 60 months prior to diagnosis. The detection discrimination statistics were calculated for risk scores by strata of lag-time. For CA19-9, in univariate marker analyses, C-statistics to distinguish future pancreatic cancer patients from cancer-free individuals were 0.80 for plasma taken ≤6 months before diagnosis, and 0.71 for >6-18 months; for ApoA2-ATQ/AT, C-statistics were 0.62, and 0.65, respectively. Joint models based on ApoA2-ATQ/AT plus CA19-9 significantly improved discrimination within >6-18 months (C = 0.74 vs. 0.71 for CA19-9 alone, p = 0.022) and ≤ 18 months (C = 0.75 vs. 0.74, p = 0.022). At 98% specificity, and for lag times of ≤6, >6-18 or ≤ 18 months, sensitivities were 57%, 36% and 43% for CA19-9 combined with ApoA2-ATQ/AT, respectively, vs. 50%, 29% and 36% for CA19-9 alone. Compared to CA19-9 alone, the combination of CA19-9 and ApoA2-ATQ/AT may improve detection of pancreatic cancer up to 18 months prior to diagnosis under usual care, and may provide a useful first measure for pancreatic cancer detection prior to imaging.

Ceruloplasmin, transferrin and apolipoprotein A-II play important role in treatment's follow-up of paracoccidioidomycosis patients.

Paracoccidioidomycosis (PCM) is a systemic disease caused by thermodymorphic fungi of the Paracoccidioides brasiliensis complex, (Paracoccidioides spp.). Patients with PCM reveal specific cellular immune impairment. Despite the effective treatment, quiescent fungi can lead to relapse, usually late, the serological diagnosis of which has been deficient. The present study was carried out with the objective of investigating a biomarker for the identification of PCM relapse and another molecule behaving as an immunological recovery biomarker; therefore, it may be used as a cure criterion. In the evolutionary analysis of the proteins identified in PCM patients, comparing those that presented with those that did not reveal relapse, 29 proteins were identified. The interactions observed between the proteins, using transferrin and haptoglobin, as the main binding protein, were strong with all the others. Patient follow-up suggests that cerulosplamin may be a marker of relapse and that transferrin and apolipoprotein A-II may contribute to the evaluation of the treatment efficacy and avoiding a premature decision.

Insulin resistance involvement in prevalence of familial dysbetalipoproteinemia in ε2ε2 subjects by Bayesian network modeling.

OBJECTIVE: Familial dysbetalipoproteinemia (FD) or Type III hyperlipoproteinemia is closely associated with the ε2ε2 genotype of the common APOE polymorphism although not all ε2 homozygotes develop FD indicating that additional factors play a role including insulin resistance (IR). The current study was undertaken to explore relationships and influences among factors, especially IR, that might elucidate FD progression pathways. METHODS: Bayesian network (BN) modeling, a probabilistic graphical exploratory data analysis tool that portrays relationships and influences among variables as simple diagrams, was applied to 52 e2e2 subjects. An algorithm based on apolipoprotein and lipid values identified 24 subjects having FD. BN modeling parameters included plasma apoE, HDL cholesterol (HDL-C), apolipoprotein A-I (apoA-I), apolipoprotein A-II (apoA-II), apoA-I/HDL-C ratio, apoA-II/HDL-C ratio, insulin, and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). RESULTS: Modeling resulted in twenty network graphs. Each graph revealed apoE and the apoA-II/HDL-C ratio as sole determinants of FD prevalence. BN results did not demonstrate a direct role for insulin and HOMA-IR. However, multiple graphs in the set did reveal indirect influence of IR on FD prevalence as conveyed through the apoA-II/HDL-C ratio; while all remaining graphs in the set demonstrated the apoA-II/HDL-C ratio as directly influencing insulin levels and HOMA-IR. For apoE, the other determinant of FD prevalence, results revealed no relationship with IR parameters. CONCLUSIONS: In so far as insulin levels and HOMA-IR are associated with IR in e2e2 subjects, IR may act indirectly in FD progression via the apoA-II/HDL-C ratio; and/or the apoA-II/HDL-C ratio acts directly to promote IR.

Serum apolipoprotein A2 isoforms in autoimmune pancreatitis.

Recently, apolipoprotein A2 (apoA2) isoforms have been reported as candidate serum/plasma biomarkers of pancreatic cancer. However, the distribution of apoA2 isoforms in patients with autoimmune pancreatitis (AIP) has not been investigated yet. In this study, we evaluated the distribution of serum apoA2 isoforms; i.e., homodimer apoA2-ATQ/ATQ, heterodimer apoA2-ATQ/AT, and homodimer apoA2-AT/AT, in AIP patients and healthy volunteers (HV) using enzyme-linked immunosorbent assays, and the clinical characteristics and serum levels of each apoA2 isoform in 32 AIP patients and 38 HV were investigated. The calculated apoA2-ATQ/AT levels of the AIP patients were significantly lower than those of the HV, which agreed with results obtained for patients with pancreatic cancer. Interestingly, most of the AIP patients exhibited high levels of apoA2-ATQ along with low levels of apoA2-AT, indicating that the processing of the C-terminal regions of apoA2 dimer was inhibited in the AIP patients. This specific distribution of serum apoA2 isoforms might provide important information about the disease states of AIP patients and aid the differential diagnosis of AIP versus pancreatic cancer.

Roles of high apolipoprotein E blood levels and HDL in development of familial dysbetalipoproteinemia in ε2ε2 subjects.

OBJECTIVE: Familial dysbetalipoproteinemia (FD) or Type III hyperlipoproteinemia is a mixed hyperlipidemia closely associated with the ε2ε2 genotype of the common APOE polymorphism although not all homozygotes progress to FD. Unlike the polymorphism, few studies explore effects of apolipoprotein E (apoE) blood levels on FD development. Likewise, despite the known apoE2 lipoprotein binding preference for high-density lipoprotein (HDL); little work exists exploring HDL in FD. Accordingly, this study was undertaken to investigate potential roles in FD development for apoE and HDL. Additionally, insulin and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) were investigated in view of reports linking insulin resistance to FD. METHODS: APOE genotyping and levels of apoE, apolipoprotein A-I (apoA-I), apolipoprotein A-II (apoA-II), insulin, HOMA-IR, lipids, and NMR lipoprotein analysis were determined in a cohort of healthy individuals (N=7169). A lipid-based algorithm identified FD in 24 of 52 e2e2 subjects. Logistic regression modeling assessed associations of FD development with measured variables. RESULTS: Univariate models revealed associations with FD significant and positive for apoE, apoA-II/apoA-I, apoA-I/HDL-C, apoA-II/HDL-C, and HOMA-IR. For HDL-C, association was significant but inverse. Results of multivariable models containing apoE with single parameters added revealed statistical significance only for the apoA-II/HDL-C ratio (OR 10.52, 95%CI 1.17-94.79, p=0.036) concurrent with significance for apoE (OR 2.21, 95%CI 1.06-4.65, p=0.035). Interaction was not demonstrated (p=0.36). NMR results revealed for FD versus nonFD subjects generally higher levels of VLDL and small HDL and for IDL few differences. CONCLUSION: High apoE and high apoA-II/HDL-C independently associate with FD development in ε2ε2 individuals.

Apolipoprotein C-III in the high-density lipoprotein proteome of cerebral lacunar infarction patients impairs its anti-inflammatory function.

High-density lipoprotein (HDL) proteomic study has identified substantial changes associated with various disease states. In the current study, the HDL proteomes in patients with cerebral lacunar infarction (LACI) and control subjects were investigated. A total of 12 LACI patients without evident large vessel occlusions and 12 controls were enrolled in the study. The HDL fraction from each sample was isolated from the plasma by ultracentrifugation. The protemics of the HDL were investigated using nano liquid chromatography coupled to tandem mass spectrometry. There were 55 proteins identified as differentially expressed in the LACI and control groups. Among the 55 proteins, 33 were upregulated and 22 were downregulated in the patients with LACI. The identified proteins were associated with numerous molecular functions, including lipid and cholesterol transport, lipid metabolism, inflammatory response, the complement and coagulation pathway, metal ion metabolism, hemostasis and endopeptidase inhibitory activity. Serum amyloid A, apolipoprotein C (apoC-III) and apolipoprotein A-II (apoA-II) were selected to confirm the proteomics results via western blotting. HDL from the LACI patients exhibited an impaired ability to inhibit the binding of THP-1 cells to endothelial cells compared with the controls (P<0.01). ApoC-III-rich HDL also had a significantly reduced ability to inhibit the binding of THP-1 cells to endothelial cells (P<0.01). The expression of vascular cell adhesion molecule-1 protein by the endothelial cells exhibited a similar pattern of response to the different HDL samples. In conclusion, the present study demonstrates major modifications of the HDL proteome in patients with LACI. The ApoC-III enrichment of the HDL of patients with LACI may cause a reduction in the anti-inflammatory ability of HDL, which may contribute to the progression of the disease.

ApoA-I/A-II-HDL positively associates with apoB-lipoproteins as a potential atherogenic indicator.

BACKGROUND: We recently reported distinct nature of high-density lipoproteins (HDL) subgroup particles with apolipoprotein (apo) A-I but not apoA-II (LpAI) and HDL having both (LpAI:AII) based on the data from 314 Japanese. While plasma HDL level almost exclusively depends on concentration of LpAI having 3 to 4 apoA-I molecules, LpAI:AII appeared with almost constant concentration regardless of plasma HDL levels having stable structure with two apoA-I and one disulfide-dimeric apoA-II molecules (Sci. Rep. 6; 31,532, 2016). The aim of this study is further characterization of LpAI:AII with respect to its role in atherogenesis. METHODS: Association of LpAI, LpAI:AII and other HDL parameters with apoB-lipoprotein parameters was analyzed among the cohort data above. RESULTS: ApoA-I in LpAI negatively correlated with the apoB-lipoprotein parameters such as apoB, triglyceride, nonHDL-cholesterol, and nonHDL-cholesterol + triglyceride, which are apparently reflected in the relations of the total HDL parameters to apoB-lipoproteins. In contrast, apoA-I in LpAI:AII and apoA-II positively correlated to the apoB-lipoprotein parameters even within their small range of variation. These relationships are independent of sex, but may slightly be influenced by the activity-related CETP mutations. CONCLUSIONS: The study suggested that LpAI:AII is an atherogenic indicator rather than antiatherogenic. These sub-fractions of HDL are to be evaluated separately for estimating atherogenic risk of the patients.

Redox status of serum apolipoprotein E and its impact on HDL cholesterol levels.

BACKGROUND: Apolipoprotein E (apoE) is closely involved in the pathogenesis of apoE-related diseases, such as Alzheimer's disease and cardiovascular disease. The redox modulation of cysteine-thiols in a protein is involved in various pathophysiological regulations; however, that of apoE has not been studied in detail. Herein, we devised an analytical method to determine the redox status of serum apoE and assessed its relation to serum cholesterol levels and apoE phenotype. METHODS: The present method was based on a band shift assay, using a photocleavable maleimide-conjugated polyethylene glycol. RESULTS: The basic characteristics of the present method were found to be satisfactory to determine the redox status of serum apoE quantitatively. Serum apoE was separated into its reduced-form (r-), non-reduced-form (nr-), apoE-AII complex, and homodimer using this method. R-apoE could be detected as a 40-kDa band, whereas nr-apoE remained as monomeric apoE. R-apoE displayed a preference for VLDL; however, the levels showed the correlation with HDL-cholesterol levels (p<0.005). Redox status of serum apoE was significantly different among apoE phenotypes. The quantitative ratios of nr-apoE to total apoE in serum from subjects with apoE4/E3 were higher than in serum from subjects with apoE3/E3 (p<0.0001) and apoE3/E2 (p<0.001). CONCLUSION: The redox status of serum apoE might be related to the synthesis of HDL. The information concerning the redox status of serum apoE provided by the present method may be a potent indicator to evaluate various apoE-related diseases.