478 resultados para Apolipoprotein CIII
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Background: We have previously demonstrated that carrying the apolipoprotein (apo) E epsilon 4 (E4+) genotype disrupts omega-3 fatty acids (n − 3 PUFA) metabolism. Here we hypothesise that the postprandial clearance of n − 3 PUFA from the circulation is faster in E4+ compared to non-carriers (E4−). The objective of the study was to investigate the fasted and postprandial fatty acid (FA) profile of triacylglycerol-rich lipoprotein (TRL) fractions: Sf >400 (predominately chylomicron CM), Sf 60 − 400 (VLDL1), and Sf 20 − 60 (VLDL2) according to APOE genotype. Methods: Postprandial TRL fractions were obtained in 11 E4+ (ε3/ε4) and 12 E4− (ε3/ε3) male from the SATgenε study following high saturated fat diet + 3.45 g/d of docosahexaenoic acid (DHA) for 8-wk. Blood samples were taken at fasting and 5-h after consuming a test-meal representative of the dietary intervention. FA were characterized by gas chromatography. Results: At fasting, there was a 2-fold higher ratio of eicosapentaenoic acid (EPA) to arachidonic acid (P = 0.046) as well as a trend towards higher relative% of EPA (P=0.063) in theSf >400 fraction of E4+. Total n − 3 PUFA in the Sf 60 − 400 and Sf 20 − 60 fractions were not APOE genotype dependant. At 5 h, there was a trend towards a time × genotype interaction (P=0.081) for EPA in theSf >400 fraction. When sub-groups were form based on the level of EPA at baseline within the Sf >400 fraction, postprandial EPA (%) was significantly reduced only in the high-EPA group. EPA at baseline significantly predicted the postprandial response in EPA only in E4+ subjects (R2 = 0.816). Conclusion: Despite the DHA supplement contain very low levels of EPA, E4+ subjects with high EPA at fasting potentially have disrupted postprandial n − 3 PUFA metabolism after receiving a high-dose of DHA. Trial registration: Registered at clinicaltrials.gov/show/NCT01544855.
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BACKGROUND:Apolioprotein E (APOE) genotype is reported to influence a person's fasting lipid profile and potentially the response to dietary fat manipulation. The impact of APOE genotype on the responsiveness to meals of varying fat composition is unknown. OBJECTIVE:We examined the effect of meals containing 50 g of fat rich in saturated fatty acids (SFAs), unsaturated fatty acids (UNSATs), or SFAs with fish oil (SFA-FO) on postprandial lipemia. METHOD:A randomized, controlled, test meal study was performed in men recruited according to the APOE genotype (n = 10 APOE3/3, n = 11 APOE3/E4). RESULTS:For the serum apoE response (meal × genotype interaction P = 0.038), concentrations were on average 8% lower after the UNSAT than the SFA-FO meal in APOE4 carriers (P = 0.015) only. In the genotype groups combined, there was a delay in the time to reach maximum triacylglycerol (TG) concentration (mean ± SEM: 313 ± 25 vs. 266 ± 27 min) and higher maximum nonesterified fatty acid (0.73 ± 0.05 vs. 0.60 ± 0.03 mmol/L) and glucose (7.92 ± 0.22 vs. 7.25 ± 0.22 mmol/L) concentrations after the SFA than the UNSAT meal, respectively (P ≤ 0.05). In the Svedberg flotation rate 60-400 TG-rich lipoprotein fraction, meal × genotype interactions were observed for incremental area under the curve (IAUC) for the TG (P = 0.038) and apoE (P = 0.016) responses with a 58% lower apoE IAUC after the UNSAT than the SFA meal (P = 0.017) in the E4 carriers. CONCLUSIONS:Our data indicate that APOE genotype had a modest impact on the postprandial response to meals of varying fat composition in normolipidemic men. The physiologic importance of greater apoE concentrations after the SFA-rich meals in APOE4 carriers may reflect an impact on TG-rich lipoprotein clearance from the circulation. This trial was registered at clinicaltrials.gov as NCT01522482.
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The interaction of a designed bioactive lipopeptide C16-GGGRGDS, comprising a hexadecyl lipid chain attached to a functional heptapeptide, with the lipid-free apoliprotein, Apo-AI, is examined. This apolipoprotein is a major component of high density lipoprotein and it is involved in lipid metabolism and may serve as a biomarker for cardiovascular disease and Alzheimers’ disease. We find via isothermal titration calorimetry that binding between the lipopeptide and Apo-AI occurs up to a saturation condition, just above equimolar for a 10.7 μM concentration of Apo-AI. A similar value is obtained from circular dichroism spectroscopy, which probes the reduction in α-helical secondary structure of Apo-AI upon addition of C16-GGGRGDS. Electron microscopy images show a persistence of fibrillar structures due to self-assembly of C16-GGGRGDS in mixtures with Apo-AI above the saturation binding condition. A small fraction of spheroidal or possibly “nanodisc” structures was observed. Small-angle X-ray scattering (SAXS) data for Apo-AI can be fitted using a published crystal structure of the Apo-AI dimer. The SAXS data for the lipopeptide/ Apo-AI mixtures above the saturation binding conditions can be fitted to the contribution from fibrillar structures coexisting with flat discs corresponding to Apo-AI/lipopeptide aggregates.
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The presence of the, 4 allele of apolipoprotein E (APOE) is considered a risk factor for sporadic Alzheimer`s disease (AD). Our recent data demonstrated that the systemic modulation of oxidative stress in platelets and erythrocytes is disrupted in aging and AD. In this study, the relationship between APOE genotype and oxidative stress markers, both in AD patients and controls, was evaluated. The AD group showed an increase in the content of thiobarbituric acid-reactive substances (TBARS) and in the activities of nitric oxide synthase (NOS) and Na, K-ATPase, when compared to controls. Both groups had a similar cGMP content and superoxide dismutase activity. APOE epsilon 4 allele carriers showed higher NOS activity than non-carriers. These results suggest a possible influence of APOE genotype on nitric oxide (NO) production that might enhance the effects of age-related specific factor(s) associated with neurodegenerative disorders. Copyright (C) 2008 John Wiley & Sons, Ltd.
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The aim of the study was to verify whether post-menopausal hormone replacement therapy (HRT) modifies autoantibody titers against oxidized low-density lipoprotein (LDL) (anti-LDLoxi), against epitopes of oxidized apolipoprotein B100 and common carotid intima-media thickness (IMT) in these women. Sixty-eight women in pre-menopause (PMW) and 216 in post-menopause (POMW) were recruited; eighty-three had undergone HRT for at least 12 months, where 48 received conjugated estrogens alone (EHRT) and 35 received conjugated estrogen and medroxyprogesterone acetate (CHRT). ELISA was used to determine autoantibodies. Lipoprotein lipase (LPL), hepatic lipase (HL), cholesterol ester transfer protein (CETP) and phospholipid transfer protein (PLTP) activities were assayed by radiometric methods. IMT was measured using Doppler ultrasound. Anti-oxidized LDL and anti-D antibodies increased by 40% (p <= 0.003) and 42% (p <= 0.006), respectively, with menopause. There was a surprising and significant 7% reduction in anti-D2 antibody titers with HRT (p <= 0.050), indicating a positive effect of treatment on the immune response to oxidized LDL. Combined HRT decreased activities of HL and LPL. HRT did not change common carotid IMT, which was increased by 32% as expected after menopause (p <= 0.030). This study describes, for the first time, the protective effect of HRT on decreasing autoantibody titers against oxidized apolipoprotein B in LDL.
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A análise de um modelo de erosão é um crítico passo no desenvolvimento de uma ferramenta de predição da erosão aplicável e válida; isso é crucial para avaliar o desempenho dos modelos existentes para assegurar que as estimativas de um modelo condizem com a realidade. O objetivo do presente trabalho foi avaliar modelos para a predição do subfator cobertura e manejo (CiII) relativo à erosão entressulcos. Um experimento fatorial completo foi conduzido com cinco doses de resíduo de milho (0; 0,05; 0,15; 0,40 e 0,80 kg m-2), quatro declives e duas repetições, sob condições de prévio umedecimento para determinar as taxas de erosão entressulcos (Di) e enxurrada (R). Num primeiro experimento, foi avaliada a erodibilidade entressulcos (Ki) e o subfator cobertura e manejo (CiII), em parcelas experimentais de 0,5 x 0,75 m, em solo recentemente preparado. Num segundo experimento, foram avaliados Di, R, Ki e CiII, também em parcelas de 0,5 x 0,75 m, em solo recém- preparado. Os valores de Di, R, Ki e CiII, obtidos no segundo experimento, foram utilizados na avaliação dos modelos testados. Os modelos CiII = e-2,50 CS/100 e CiII = e -2,238 CS/100 apresentaram boas estimativas para o subfator CiII.
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HIV infection is associated with disturbances in lipid metabolism due to a host's response mechanism and the current antiretroviral therapy. The pathological appearance and progression of atherosclerosis is dependent on the presence of injurious agents in the vascular endothelium and variations in different subsets of candidate genes. Therefore, the Hha I polymorphism in the apolipoprotein E gene was evaluated in addition to triglycerides, total cholesterol, very low-density lipoprotein (VLDL), LDL, high-density lipoprotein (HDL), and apolipoprotein (apo) Al, B and E levels in 86 Brazilian HIV-infected patients and 29 healthy controls. The allele frequency for apoE in the HIV-infected group and controls was in agreement with data on the Brazilian population. Dyslipidemia was observed in the HIV group and verified by increased levels of triglycerides, VLDL and apoE, and decreased levels of HDL and apoAl. The greatest abnormalities in these biochemical variables were shown in the HIV-infected individuals whose immune function was more compromised. The effect of the genetic variation at the APOE gene on biochemical variables was more pronounced in the HIV-infected individuals who carried the apoE2/3 genotype. The highly active antiretroviral therapy (HAART)-receiving group presented increased levels of total cholesterol and apoE. Dyslipidemia was a predictable consequence of HIV infection and the protease inhibitors intensified the increase in apoE values.
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The genetic basis for dementias is complex. A common polymorphism in the apolipoprotein E (APOE) gene is considered to be the major risk factor in families with sporadic and late-onset Alzheimer's disease as well as in the general population. The distribution of alleles and genotypes of the APOE gene in late-onset Alzheimer's disease (N = 68), other late-life dementias (N = 39), and in cognitively normal controls (N = 58) was determined, as also was the risk for Alzheimer's disease associated with the epsilon4 allele. Peripheral blood samples were obtained from a total of 165 individuals living in Brazil aged 65-82 years. Genomic DNA was amplified by the polymerase chain reaction and the products were digested with HhaI restriction enzyme. APOE epsilon2 frequency was considerably lower in the Alzheimer's disease group (1%), and the epsilon3 allele and epsilon3/epsilon3 genotype frequencies were higher in the controls (84 and 72%, respectively) as were the epsilon4 allele and epsilon3/epsilon4 genotype frequencies in Alzheimer's disease (25 and 41%, respectively). The higher frequency of the epsilon4 allele in Alzheimer's disease confirmed its role as a risk factor, while epsilon2 provided a weak protection against development of the disease. However, in view of the unexpectedly low frequency of the epsilon4 allele, additional analyses in a more varied Brazilian sample are needed to clarify the real contribution of apolipoprotein E to the development of Alzheimer's disease in this population.
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In previous studies, it was shown that lipid microemulsions resembling LDL (LDE) but not containing protein, acquire apolipoprotein E when injected into the bloodstream and bind to LDL receptors (LDLR) using this protein as ligand. Aiming to evaluate the effects of apolipoprotein (apo) B-100 on the catabolism of these microemulsions, LDE with incorporated apo B-100 (LDE-apoB) and native LDL, all labeled with radioactive lipids were studied after intraarterial injection into Wistar rats. Plasma decay curves of the labels were determined in samples collected over 10 h and tissue uptake was assayed from organs excised from the animals sacrificed 24 h after injection. LDE-apo B had a fractional clearance rate (FCR) similar to native LDL (0.40 and 0.33, respectively) but both had FCR pronouncedly smaller than LDE (0.56, P<0.01). Liver was the main uptake site for LDE, LDE-apoB, and native LDL, but LDE-apoB and native LDL had lower hepatic uptake rates than LDE. Pre-treatment of the rats with 17 alpha-ethinylestradiol, known to upregulate LDLR, accelerated the removal from plasma of both LDE and LDE-apoB, but the effect was greater upon LDE than LDE-apoB. These differences in metabolic behavior documented in vivo can be interpreted by the lower affinity of LDLR for apo B-100 than for apo E, demonstrated in in vitro studies. Therefore, our study shows in vivo that, in comparison with apo E, apo B is a less efficient ligand to remove lipid particles such as microemulsions or lipoproteins from the intravascular compartment. (C) 1999 Elsevier B.V. B.V. All rights reserved.
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Abstract. Background: This study investigated the hypothesis that long-term orange juice consumption (≥ 12 months) was associated with low risk factors for cardiovascular disease in adult men and women with normal and moderately high cholesterol blood levels. Methods. The sample consisted of 103 men (18-66 y) and 26 women (18-65 y); all were employees of an orange juice factory with daily access to free orange juice. The results showed that 41% of the individuals consumed 2 cups (480 mL) of orange juice per day for at least twelve months, while 59% of the volunteers are non-consumers of orange juice. Results: Orange juice consumers with normal serum lipid levels had significantly lower total cholesterol (-11%, p <0.001), LDL-cholesterol (-18%, p < 0.001), apolipoprotein B (apo B) (-12%, p < 0.01) and LDL/HDL ratio (-12%, p < 0.04) in comparison to non-consumers, as did the consumers with moderate hypercholesterolemia: lower total cholesterol (-5%, p <0.02), LDL-cholesterol (-12%, p <0.03), apolipoprotein B (-12%, p <0.01) and LDL/HDL ratio (-16%, p <0.05) in comparison the non-consumers counterparts. Serum levels of homocysteine, HDL- cholesterol and apolipoprotein A-1, body composition and the dietary intake of food energy and macronutrients did not differ among orange juice consumers and non-consumers, but vitamin C and folate intake was higher in orange juice consumers. Conclusion: Long-term orange juice consumers had lower levels of total cholesterol, LDL-cholesterol, apo B and LDL/HDL ratio and an improvement of folate and vitamin C in their diet. © 2013 Aptekmann and Cesar; licensee BioMed Central Ltd.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Atherosclerosis and vascular calcification (VC) progression in chronic kidney disease is favored by disturbances of mineral metabolism. We compared the effect of phosphate binder lanthanum (La) carbonate with sevelamer-HCl on atherosclerosis, VC and bone structure and function in mice with chronic renal failure (CRF). Apolipoprotein E-deficient (apoE(-/-)) mice were randomized to one non-CRF and three CRF groups, fed with standard diet (one non-CRF and one CRF) or diet supplemented with either 3% lanthanum carbonate (La3%) or 3% sevelamer-HCl (Sev3%). Both La3% and Sev3% supplemented CRF mice displayed a decrease of serum phosphorus, calcification at both intimal and medial aortic sites and atherosclerosis. This was associated with a reduction of plaque Type I collagen expression by both binders and of positive nitrotyrosine staining in response to sevelamer-HCl only. Increased mineral apposition and bone formation rates in unsupplemented CRF mice were reduced by Sev3% but not by La3%. The beneficial effects of La carbonate and sevelamer-HCl on the progression of VC and atherosclerosis in CRF mice could be mainly due to a decrease in phosphate retention and likewise a reduction of arterial Type I collagen expression. The effect of La carbonate differed from that of sevelamer-HCl in that it did not appear to exert its vascular effects via changes in oxidative stress or bone remodeling in the present model.
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Abstract Background Apolipoprotein E (apoE) is a key component of the lipid metabolism. Polymorphisms at the apoE gene (APOE) have been associated with cardiovascular disease, lipid levels and lipid-lowering response to statins. We evaluated the effects on APOE expression of hypercholesterolemia, APOE ε2/ε3/ε4 genotypes and atorvastatin treatment in Brazilian individuals. The relationship of APOE genotypes and plasma lipids and atorvastatin response was also tested in this population. Methods APOE ε2/ε3/ε4 and plasma lipids were evaluated in 181 normolipidemic (NL) and 181 hypercholesterolemic (HC) subjects. HC individuals with indication for lowering-cholesterol treatment (n = 141) were treated with atorvastatin (10 mg/day/4-weeks). APOE genotypes and APOE mRNA in peripheral blood mononuclear cells (PBMC) were analyzed by TaqMan real time PCR. Results HC had lower APOE expression than NL group (p < 0.05) and individuals with low APOE expression showed higher plasma total and LDL cholesterol and apoB, as well as higher apoAI (p < 0.05). Individuals carrying ε2 allele have reduced risk for hypercholesterolemia (OR: 0.27, 95% I.C.: 0.08-0.85, p < 0.05) and NL ε2 carriers had lower total and LDL cholesterol and apoB levels, and higher HDL cholesterol than non-carriers (p < 0.05). APOE genotypes did not affect APOE expression and atorvastatin response. Atorvastatin treatment do not modify APOE expression, however those individuals without LDL cholesterol goal achievement after atorvastatin treatment according to the IV Brazilian Guidelines for Dyslipidemia and Atherosclerosis Prevention had lower APOE expression than patients with desirable response after the treatment (p < 0.05). Conclusions APOE expression in PBMC is modulated by hypercholesterolemia and the APOE mRNA level regulates the plasma lipid profile. Moreover the expression profile is not modulated neither by atorvastatin nor APOE genotypes. In our population, APOE ε2 allele confers protection against hypercholesterolemia and a less atherogenic lipid profile. Moreover, low APOE expression after treatment of patients with poor response suggests a possible role of APOE level in atorvastatin response.
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Apolipoprotein J (ApoJ) ist ein sezerniertes heterodimeres 80kDa Glykoprotein mit zytoprotektiven und antiinflammatorischen Eigenschaften, das ein nahezu ubiquitäres Expressionsmuster aufweist. Eine stark erhöhte ApoJ-Expression ist mit neurodegenerativen Erkrankungen, Atherosklerose, myokardialem Infarkt sowie einer Vielzahl anderer pathophysiologischer Bedingungen assoziiert. Die potentielle Bedeutung von ApoJ umfasst eine Funktion als extrazelluläres Chaperon, Komplementinhibitor, NF-kB-Inhibitor sowie eine Beteiligung an der Endozytose von nekrotischen Zellfragmenten. Unter Bedingungen, die zu einer massiven Akkumulation von absterbenden Zellen führen, ist eine vermehrte Expression von ApoJ auf die überlebenden Nachbarzellen in den betroffenen Geweben beschränkt. Die molekularen Mechanismen, die dieser gesteigerten ApoJ-Genexpression zugrunde liegen, sind jedoch unbekannt. Untersuchungen unserer Arbeitsgruppe konnten zeigen, dass eine Inkubation mit nekrotischem Zellmaterial in vitro eine Akkumulation von ApoJ-mRNA in Fibroblasten der Zelllinie Rat1 induziert, was darauf hindeutet, dass unter pathophysiologischen Bedingungen von nekrotischen Zellen exponierte bzw. freigesetzte Faktoren zu einer gesteigerten ApoJ-Genexpression in umliegenden vitalen Zellen beitragen können. Die im Rahmen der vorliegenden Arbeit durchgeführten Untersuchungen zeigen eine Korrelation zwischen der Expression von Toll-like Rezeptoren (TLRs) in Fibroblasten (Rat1), glatten Gefäßmuskelzellen (CRL2018) sowie embryonalen Dottersackzellen (10A) und einer durch nekrotische Zellen induzierten ApoJ-mRNA-Expression in diesen Zelllinien. Es wird angenommen, dass TLRs neben pathogenassoziierten Strukturen (PAMPs) auch durch körpereigene Agonisten wie Hitzeschockproteine und Nukleinsäuren aktiviert werden. In weiterführenden Experimenten stellte sich unter anderem heraus, dass neben nekrotischen Zellen auch der TLR3-spezifische Agonist Poly(I:C), eine synthetische doppelsträngige RNA, ausschließlich in den beiden TLR3-exprimierenden Zelllinien CRL2018 und Rat1, nicht jedoch in TLR3-defizienten 10A-Zellen, die ApoJ-mRNA-Expression induziert. Darüber hinaus führt auch die Inkubation mit eukaryotischer RNA (Gesamt-RNA, t-RNA) zu einer Akkumulation von ApoJ-mRNA in CRL2018-Zellen. Die Ergebnisse dieser Arbeit zeigen erstmals, dass die Expression von ApoJ-mRNA durch extrazelluläre Ribonukleinsäuren in TLR3-abhängiger Weise induziert wird, was darauf hindeutet, dass in verletzten Geweben aus post-apoptotischen oder nekrotischen Zellen freigesetzte Ribonukleinsäuren zu einer vermehrten ApoJ-Genexpression in vitalen Nachbarzellen beitragen.
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Die massive Bildung und Ablagerung von aggregiertem Amyloid Beta-Peptid im Gehirn wird allgemein als zentrales Ereignis im Rahmen des Neurodegenerationsprozesses der Alzheimer Demenz betrachtet. Als einer der ursächlichen Risikofaktoren gilt das Vorliegen des ε4-Allels des Apolipoprotein E. Die Alzheimer´sche Krankheit ist dabei in sehr vielfältige Weise mit Apolipoprotein E verknüpft. ApoE begünstigt isoformenabhängig Aβ-Ablagerungen, ApoE-Fragmente kommen im Gehirn und der Cerebrospinalflüssigkeit von Alzheimer Patienten vor und ApoE ist darüber hinaus als Cholesterintransportprotein über den zellulären Cholesterinstoffwechsel mit der Amyloidbildung verknüpft. Mit Hilfe einer Doppeltransfektion von ApoE und ADAM10 in HEK-Zellen und durch Studien mit Inhibitoren der ADAM-Familie an HepG-2-Zellen wurde in vitro gezeigt, dass ApoE nicht durch α-Sekretasen der ADAM-Familie gespalten wird. Weiterhin konnte bewiesen werden, dass ApoE in Astrogliomazellen keinen Einfluss auf die APP-Prozessierung ausübt. Durch in vitro Modulation des Cholesteringehaltes an Astrogliomazellen mit MβCD und seine Cholesterin-Komplexverbindungen ist gezeigt worden, dass die ApoE-Sekretion durch abnehmenden Cholesteringehalt gesenkt wird. Indem Statine alleine oder in Kombination mit Isoprenylierungssubstraten eingesetzt wurden ist der Beweis erbracht worden, dass Statine in vitro die ApoE-Sekretionsinhibition alleine durch Hemmung der Cholesterinbiosynthese bewirken. Bestätigt wurde dies weiterhin durch Experimente mit Isoprenylierungsinhibitoren. Aus dem Wirkmechanismus von Statinen auf die ApoE-Sekretionssenkung leitet sich womöglich der für bestimmte Statine berichtete neuroprotektive Effekt bei Morbus Alzheimer in retrospektiven Humanstudien ab, der sich durch reine Cholesterinsenkung nicht erklären lässt. Im Zusammenhang mit der Cholesterinhomöostase und dem gesteigerten 24(S)-Hydroxycholesterinspiegel bei Morbus Alzheimer, haben die Ergebnisse gezeigt, dass 24(S)-Hydroxycholesterin [24(S)-OH-chol] zur ApoE-Sekretions- und Expressionssteigerung führt. In dieser Arbeit konnte erstmals der Nachweis erbracht werden, dass der stimulatorische Effekt von 24(S)-OH-Chol durch gleichzeitige Lovastatingabe reduziert werden kann. Dies stellt einen möglichen Ansatz im Kampf gegen die Alzheimer Demenz dar. Weiterführend müssen diese Ergebnisse noch in vivo beispielsweise durch Versuche an ApoE-transgenen Mäusen bestätigt werden. Darüber hinaus könnte nach einer Statintherapie der ApoE-Gehalt in humaner, cerebrospinaler Flüssigkeit ermittelt werden.