Os Ácidos Graxos Poli-insaturados Ômega-6 e Ômega-3 Presentes nas Hemácias Exercem uma Influência Distinta sobre o Tamanho das Partículas de LDL e suas Alterações Estruturais / Red Blood Cells' Omega-6 and Omega-3 Polyunsaturated Fatty Acids Have a Distinct Influence on LDL Particle Size and its Structural Modifications

Resumo Fundamento Embora os ácidos graxos poli-insaturados ômega-3 e ômega-6 (AGPIs n-3 e n-6) tenham efeitos bem conhecidos sobre os fatores de risco de doenças cardiovasculares (DCV), ainda existe um conhecimento limitado sobre como eles afetam os indicadores de qualidade da LDL. Objetivo Avaliar as associações dos AGPIs n-3 e n-6 de hemácias com o tamanho da partícula da LDL, LDL-c pequena e densa (sdLDL-c) e com LDL eletronegativa [LDL(-)] em adultos com fatores de risco para DCV. Métodos Estudo transversal com 335 homens e mulheres de 30 a 74 anos com, pelo menos, um fator de risco cardiovascular. Foram realizadas análises de parâmetros bioquímicos, como glicose, insulina, HbA1c, proteína C reativa (PCR), perfil lipídico, subfrações de lipoproteínas, partícula eletronegativa de LDL [LDL(-)] e seu autoanticorpo, e os AGPIs n-3 e n- 6 de hemácias. Os testes t independente/teste de Mann-Whitney, ANOVA unidirecional/teste de Kruskal-Wallis e regressões lineares múltiplas foram aplicados. Todos os testes foram bilaterais e um valor de p inferior a 0,05 foi considerado estatisticamente significativo. Resultados A relação n-6/n-3 de hemácias foi associada ao aumento dos níveis de LDL(-) (β = 4,064; IC de 95% = 1,381 - 6,748) e sdLDL-c (β = 1,905; IC de 95% = 0,863 - 2,947), e redução do tamanho das partículas de LDL (β = -1,032; IC de 95% = -1,585 − -0,478). Individualmente, os AGPIs n-6 e n-3 apresentaram associações opostas com esses parâmetros, realçando os efeitos protetores do n-3 e evidenciando os possíveis efeitos adversos do n-6 na qualidade das partículas de LDL. Conclusão O AGPI n-6, presente nas hemácias, foi associado ao aumento do risco cardiometabólico e à aterogenicidade das partículas de LDL, enquanto o AGPI n-3 foi associado a melhores parâmetros cardiometabólicos e à qualidade das partículas de LDL.

Abstract Background While Omega-3 and omega-6 polyunsaturated fatty acids (n-3 and n-6 PUFAs) have established effects on cardiovascular disease (CVD) risk factors, little is known about their impacts on LDL quality markers. Objective To assess the associations of n-3 and n-6 PUFA within red blood cells (RBC) with LDL particle size, small dense LDL-c (sdLDL-c), and electronegative LDL [LDL(-)] in adults with CVD risk factors. Methods Cross-sectional study involving 335 men and women aged 30 to 74 with at least one cardiovascular risk factor. Analyses were conducted on biochemical parameters, such as glucose, insulin, HbA1c, C-reactive protein (CRP), lipid profile, lipoprotein subfractions, electronegative LDL particle [LDL(-)] and its autoantibody, and RBC n-3 and n-6 PUFAs. Independent t-test/Mann-Whitney test, one-way ANOVA/Kruskal-Wallis test, and multiple linear regressions were applied. All tests were two-sided, and a p-value of less than 0.05 was considered statistically significant. Results The RBC n-6/n-3 ratio was associated with increased LDL(-) (β = 4.064; 95% CI = 1.381 - 6.748) and sdLDL-c (β = 1.905; 95% CI = 0.863 - 2.947) levels, and reduced LDL particle size (β = -1.032; 95% CI = -1.585 − -0.478). Separately, n-6 and n-3 PUFAs had opposing associations with those parameters, reinforcing the protective effects of n-3 and showing the potential negative effects of n-6 on LDL particle quality. Conclusion RBC n-6 PUFA was associated with increased cardiometabolic risk and atherogenicity of LDL particles, while n-3 PUFA was associated with better cardiometabolic parameters and LDL particle quality.

Lectin-like oxidized low-density lipoprotein receptor-1 and ischemic stroke / 国际脑血管病杂志

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a member of C-type lectin-like receptor family.It can recognize many ligands and is the main receptor of oxidized low-density lipoprotein for inducing vascular endothelial dysfunction.Early studies focused on the role of LOX-1 in atherosclerosis and diabetes mellitus.Recent studies have shown that LOX-1 is closely associated with ischemic stroke.This article reviews the biological characteristics of LOX-1 and its association with ischemic stroke.

Efectos inflamatorios, oxidativos y aterogénicos del receptor endotelial de la lipoproteína de baja densidad oxidada-1 / Inflammatory, oxidative and atherogenic effects of endothelial lectin-like receptor of oxidized low density lipoprotein-1 / Efeitos inflamatórios, oxidativos e aterogênicos do receptor endotelial da lipoproteína de baixa densidade oxidativa-1

LOX-1 es un receptor endotelial de la familia de las lectinas. Su actividad biológica tiene un fuerte impacto en los fenómenos inflamatorios, oxidativos y aterogénicos endoteliales. Cuando se conoció el receptor de la lipoproteína de baja densidad (RLDL) y su regulación, se afirmó el papel aterogénico del colesterol transportado en esta lipoproteína (C-LDL). Este papel de las lipoproteínas fue la base de la denominación de dislipoproteinemias en reemplazo de dislipemias. En condiciones post-prandiales, las lipoproteínas ricas en triglicéridos, como quilomicrones y lipoproteínas de muy baja densidad (VLDL), son degradadas por la lipoproteína lipasa (LPL) de la pared vascular, produciéndose remanentes de quilomicrones (RQ) y lipoproteínas de densidad intermedia (IDL), respectivamente, que en conjunto se denominan lipoproteínas remanentes (RLPs). Dependiendo del estrés oxidativo las RLPs son oxidables y pueden unirse al LOX-1. También se liberan ácidos grasos que injurian células endoteliales y contribuyen a abrir brechas en el endotelio, que en condiciones fisiológicas es una barrera de células con uniones estrechas. El dominio intracelular de LOX-1 regula el reconocimiento de lipoproteínas de baja densidad oxidadas (LDLOX) y de RLPs. Además, posee un efecto dependiente de los radicales reactivos de oxígeno (ROS). Su dominio transmembrana actúa en el pasaje de LDLOX y monocitos al subendotelio. La inhibición de LOX-1 con anticuerpos específicos impide su unión con LDLOX, restableciendo la barrera entre el lumen vascular y el subendotelio. En cambio, las LDLOX unidas al dominio transmembrana, producen apoptosis de las células endoteliales y suprimen uniones estrechas intercelulares en el endotelio, facilitando la actividad de las moléculas de adhesión leucocitarias que promueven el pasaje al subendotelio de los elementos del lumen, tales como monocitos, plaquetas, LDLOX, RLPs oxidables y lipoproteínas (a) (Lp(a)) semejantes al plasminógeno. Las LDLOX subendoteliales aumentan la movilidad de células musculares lisas. Los monocitos subendoteliales se establecen como residentes, e incorporan LDLOX, convirtiéndose sucesivamente en macrófagos, células espumosas y lesiones aterogénicas. Sin embargo, desde Assmann G y su estudio PROCAM no puede ignorarse el papel de los triglicéridos y colesterol de lipoproteínas de alta densidad (C-HDL) como componentes del cuadro de riesgo en ECV.

LOX-1 is an endothelial receptor belonging to the family of lectins. Its biological activity has a strong impact on inflammatory, oxidative and atherogenic phenomena in endothelium. When Low Density Lipoprotein receptor (RLDL) and its regulation were known, the atherogenic role of the cholesterol transported in LDL (LDL-C) was confirmed. This lipoprotein role in atherosclerosis was the base to use the term dyslipoproteinemia instead of dyslipidemia. In post-prandial conditions, triglyceride-rich lipoproteins like chylomicrons and very low-density lipoproteins (VLDL), are degraded by lipoprotein lipase (LPL) on the vascular wall, with the resultant formation of chylomicron remnants (CR) and intermediate density lipoproteins (IDL) respectively, which as a whole are called remnant lipoproteins (RLPs). Depending on oxidative stress, RLPs are oxidized and then they can bind the LOX-1. In this process, fatty acids are also released, injuring endothelial cells and contributing to open gaps in endothelium, which under physiological conditions, is a barrier of cells with tight junctions. The intracellular domain of LOX-1 regulates the recognition of oxidized LDL (oxLDL) and RLPs, and its effect depends on reactive oxygen species (ROS). LOX-1 transmembrane domain acts in the passage of oxLDL and monocytes to the sub-endothelium. Inhibition of LOX-1 by specific antibodies prevents its binding with OxLDL, restoring the barrier between the vascular lumen and sub-endothelium. By contrast, the oxLDL, attached to the transmembrane domain, produce apoptosis of endothelial cells and the suppression of narrow intercellular junctions in the endothelium. Thus, enabling the activity of leucocyte adhesion molecules that promote the transfer to subendothelial elements lumen of monocytes, platelets, oxLDL, oxidized RLPs and lipoprotein (a) (Lp (a)), similar to plasminogen such as. Sub-endothelial OxLDL increase the mobility of smooth muscle cells. Sub-endothelial monocytes establish as resident, up-take oxLDL and successively become into macrophages, foam cells and atherosclerotic lesions. However, since Assman’s PROCAM study, the role of triglycerides and High Density Lipoprotein-cholesterol (HDL-C), as components of cardiovascular risk, cannot be ignored.

LOX-1 é um receptor endotelial da família das lectinas. Sua atividade biológica tem um importante impacto nos fenômenos inflamatórios, oxidativos e aterogênicos endoteliais. Quando foi conhecido o receptor da lipoproteína de baixa densidade (RLDL) e sua regulação, afirmou-se o papel aterogênico do colesterol transportado nesta lipoproteína (C-LDL). Este papel das lipoproteínas foi a base da denominação de dislipoproteinemias em substituição de dislipidemias. Em condições pós-prandiais, as lipoproteínas ricas em triglicérides como quilomícrons e Lipoproteínas de muito baixa densidade (VLDL) são degradadas pela lipoproteína lipase (LPL) da parede vascular, produzindo remanescentes de quilomícrons (RQ) e lipoproteínas de densidade intermediária (IDL) respectivamente, que em conjunto são chamadas lipoproteínas remanescentes (RLPs). Dependendo do estresse oxidativo, as RLPs são oxidáveis e podem se ligar ao LOX-1. Também são liberados ácidos graxos que injuriam células endoteliais e contribuem na abertura de fendas no endotélio, que em condições fisiológicas é uma barreira de células com uniões estreitas. O domínio intracelular de LOX-1 regula o reconhecimento de lipoproteínas de baixa densidade oxidativa (LDLOX) e de RLPs. Também possui um efeito dependente dos radicais reativos de oxigênio (ROS). Seu domínio transmembrana atua na passagem de LDLOX e monócitos para o subendotélio. A inibição de LOX-1 com anticorpos específicos impede sua união com LDLOX restabelecendo a barreira entre o lúmem vascular e o subendotélio. Entretanto, as LDLOX ligadas ao domínio transmembrana produzem apoptose das células endoteliais e suprimem estreitas junções intercelulares no endotélio, facilitando a atividade das moléculas de adesão leucocitária que promovem a passagem para o subendotélio de elementos do lúmem, tais como monócitos, plaquetas, LDLOX, RLPs oxidáveis e lipoproteínas (a) [Lp(a)] semelhantes ao plasminogênio. As LDLOX subendoteliais aumentam a mobilidade das células musculares lisas. Os monócitos subendoteliais se estabelecem como residentes, e incorporam LDLOX, virando sucessivamente em macrófagos, células espumosas e lesões aterogênicas. No entanto, desde Assman G e seu estudo PROCAM, não pode se ignorar o papel dos triglicérides e do colesterol de lipoproteínas de alta densidade (C-HDL) como componentes do evento de risco em ECV.

Atherosclerotic risk in middle-aged women with rheumatoid arthritis / Riesgo aterosclerótico en mujeres de mediana edad con artritis reumatoide

Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease, with progressive joint destruction, leading to disability. In half of patients, mortality is associated to coronary events, caused by classical risk factors (RF) and/or the inflammatory process. Objectives: To explore the relevance of systemic inflammatory milieu in RA without the burden of traditional RF. Methods: Women with RA and free of traditional RF (n = 30) were compared against healthy women (n = 31). Body mass index, blood pressure, glycemia, serum creatinine, total cholesterol (TC), high density lipoprotein (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG) and oxidized LDL (oxLDL), erythrocyte sedimentation rate, high-sensitivity C reactive protein (hsCRP), lipid quotients for assessing risk (TC/HDLc, LDLc/HDLc, oxLDL/non HDL cholesterol, TG/HDLc), and ultrasonographic carotid intima media thickness (IMT) were estimated or measured. Results: hsCRP and oxLDL were significantly higher in RA patients. IMT values were among normality, but thickness was slightly increased in left carotid, suggesting early atherosclerotic changes. In RA patients inflammation is associated to a higher concentration of oxLDL. No atherosclerosis was proven but a slight greater thickness in left carotid foretells the development of the disease. Conclusions: In RA patients without vascular RF, a special follow up must be implemented to halt atherosclerosis development.

Antecedentes: La artritis reumatoide (AR) es una enfermedad inflamatoria crónica, con destrucción progresiva de las articulaciones, que lleva a la discapacidad. En la mitad de lospacientes, la mortalidad se asocia con eventos coronarios, causados por factores de riesgo (FR) clásicos y/o el proceso inflamatorio. Objetivo: Explorar la relevancia del medio inflamatorio sistémico en la AR sin la carga de FR tradicionales. Métodos: Las mujeres con AR, sin los FR tradicionales (n = 30) fueron comparados contra mujeres sanas (n = 31). El índice de masa corporal, presión arterial, glucemia, creatinina sérica, colesterol total (CT), lipoproteínas de alta densidad (HDL-c), colesterol de lipoproteínas de baja densidad (LDL-c), triglicéridos (TG) y LDL oxidada (LDLox), velocidad de sedimentación de los eritrocitos, proteína C reactiva de alta sensibilidad (PCR-us), cocientes de lípidos para la evaluación de riesgos (TC/HDLc, LDLc/HDLc, colesterol LDLox/noHDL, TG/HDLc), y el espesor ultrasonográfico de la capa íntima-media carotídea (IMT), fueron estimados o medidos. Resultados: hsCRP y LDLox fueron significativamente mayores en los pacientes con AR. Los valores de IMT estaban dentro de la normalidad, pero el espesor se incrementó ligeramente en la carótida izquierda, lo que sugiere cambios ateroscleróticos tempranos. En los pacientes con AR la inflamación está asociada con una mayor concentración de oxLDL. No se comprobó aterosclerosis pero un espesor ligeramente mayor en la carótida izquierda, los hace propensos a desarrollar la enfermedad. Conclusiones: En los pacientes con AR sin FR vascular, un seguimiento especial debe ser implementado para frenar el desarrollo de la aterosclerosis.

Lipoprotein associated phospholipase A2 activity & its correlation with oxidized LDL & glycaemic status in early stages of type-2 diabetes mellitus.

Background & objectives: Lipoprotein associated phospholipase A2 (Lp-PLA2) is an important risk predictor of coronary artery disease (CAD). This study was aimed to evaluate Lp-PLA2 activity and oxidized low density lipoprotein (oxLDL) in newly diagnosed patients of type 2 diabetes mellitus and to determine the correlation of Lp-PLA2 activity with oxLDL and plasma glucose levels. Methods: Blood samples were collected in patients with newly diagnosed type 2 diabetes (n=40) before any treatment was started and healthy controls (n=40). These were processed for estimating plasma glucose: fasting and post prandial, ox LDL, and Lp-PLA2 activity. The parameters in the two groups were compared. Correlation between different parameters was calculated by Pearson correlation analysis in both groups. Results: Lp-PLA2 activity (24.48 ± 4.91 vs 18.63 ± 5.29 nmol/min/ml, P<0.001) and oxLDL levels (52.46 ± 40.19 vs 33.26 ± 12.54 μmol/l, P<0.01) were significantly higher in patients as compared to those in controls. Lp-PLA2 activity correlated positively with oxLDL in both controls (r=0.414, P<0.01), as well in patients (r=0.542, P<0.01). A positive correlation between Lp-PLA2 activity and fasting plasma glucose levels was observed only in patients (r=0.348, P<0.05). Interpretation & conclusions: Result of this study implies that higher risk of CAD in patients with diabetes may be due to increase in Lp-PLA2 activity during the early course of the disease. A positive correlation between enzyme activity and fasting plasma glucose indicates an association between hyperglycaemia and increased activity of Lp-PLA2. This may explain a higher occurrence of CAD in patients with diabetes. A positive correlation between oxLDL and Lp-PLA2 activity suggests that Lp-PLA2 activity may be affected by oxLDL also.

Lectin-Like Oxidized LDL Receptor 1 Mediates the Uptake of the C-Terminal Domain of Hsp70 (A Promising Immune Adjuvant Molecule) and Antigen Peptide Complexes.

Extracellular heat shock protein 70 (Hsp70) is an adjuvant molecule that stimulates the immune system. The C-terminal domain of Hsp70 (C70), without the ATPase domain, is sufficient for antigen cross-presentation. However, the mechanism by which the receptor mediates the uptake of C70–peptide complex remains unclear. We therefore aimed to determine the process by which the receptor mediates the uptake of antigenic peptide-bound C70. Methodology: Hsp70 and C70 individually cloned into pET28a were expressed in Escherichia coli BL21 (DE3) and were purified on Ni-NTA agarose and MonoQ HR5/5. Hsp70 and C70 were labeled with Alexa 555 and Alexa 633, respectively, to detect cellular binding. HEK293 cells stably expressing lectin-like oxidized LDL receptor-1 (LOX 1) and KG-1 human dendritic-like cells were incubated with Alexa-labeled Hsp70 and C70 individually or with C70 and antigenic complexes and were observed using fluorescence microscopy. The affinity of LOX-1 toward Hsp70 and C70 was analyzed by chip assay using surface plasmon resonance, which immobilized LOX-1 ligand recognition domain. Results: HEK293 cells stably expressing LOX-1 and KG-1 cells accepted the C70– peptide and Hsp70–peptide complexes. Anti-LOX-1-neutralizing antibody inhibited the uptake of the C70–peptide complexes by KG-1 cells. The dissociation constant (KD) of C70 toward the LOX-1 extracellular domain, measured by surface plasmon resonance, was 4.02 × 10−7 M and that of the C70–peptide complex was 6.6 × 10−8 M. C70 increased the LOX-1 affinity by forming a complex with the antigen peptide. Conclusion: Our findings suggest that LOX-1 is the primary receptor for the C70–peptide and the Hsp70–peptide complexes. C70 is a promising adjuvant molecule that is internalized via LOX-1. In addition, it is convenient to prepare C70 using an E. coli expression system and C70 is more stable than full-length Hsp70.

CD36, a scavenger receptor implicated in atherosclerosis

CD36 is a membrane glycoprotein that is present on various types of cells, including monocytes, macrophages, microvascular endothelial cells, adipocytes and platelets. Macrophage CD36 participates in atherosclerotic arterial lesion formation through its interaction with oxidized low-density lipoprotein (oxLDL), which triggers signaling cascades for inflammatory responses. CD36 functions in oxLDL uptake and foam cell formation, which is the initial critical stage of atherosclerosis. In addition, oxLDL via CD36 inhibits macrophage migration, which may be a macrophage-trapping mechanism in atherosclerotic lesions. The role of CD36 was examined in in vitro studies and in vivo experiments, which investigated various functions of CD36 in atherosclerosis and revealed that CD36 deficiency reduces atherosclerotic lesion formation. Platelet CD36 also promotes atherosclerotic inflammatory processes and is involved in thrombus formation after atherosclerotic plaque rupture. Because CD36 is an essential component of atherosclerosis, defining the function of CD36 and its corresponding signaling pathway may lead to a new treatment strategy for atherosclerosis.

Level of Auto Antibody Against Oxidized LDL in Myocardial Infracted Patients.

The aim of this study was to evaluate the level of auto antibody against oxidized LDL in myocardial infracted (MI) patients and normal healthy subjects of West Bengal (India) and to establish it to be also a cofactor for MI. Patients and Methodology : This study was carried out on 285 patients with MI as well as 75 healthy volunteers of comparable age and gender as control group. Blood was collected immediately after admission of the patients. Auto antibody against oxidized LDL, Nitric Oxide and malondialdehyde (MDA) were measured in all groups. Results : Mean serum level of auto antibody against oxidized LDL, MDA, total Cholesterol and LDL Cholesterol levels (118 ± 9.0, 7.4 ± 1.3, 233 ± 30, and 145 ± 38) were significantly (p<0.05) higher in MI patients when compared with control subject. The mean serum levels of nitric oxide (NO) and HDL, cholesterol were significantly (p<0.05) lower as compared to control group. Conclusion : Significantly high level of auto antibody against oxidized LDL associated with high level of MDA, total cholesterol and decreased level of NO and HDL cholesterol appear to be the factors responsible for the increase risk of coronary artery disease i.e., myocardial infarction in the population of West Bengal, India.

Endarterium injury and the related pathway in chronic intermittent hypoxia rats / 中南大学学报(医学版)

Objective:To examine the pathological change and intima thickness of thoracic aorta, detect the serum concentration of hypoxia-inducible factor-1α(HIF-1α), oxidized LDL (ox-LDL), and pentraxin 3 (PTX3) in the rat model of chronic intermittent hypoxia (CIH), and to determine the effect of CIH on endarterium injury and its possible pathway.Methods:Twenty-four male Sprague-Dawley (SD) rats were divided into 4 groups:a CIH+N-acetylcysteine (NAC) group, a CIH+normal saline (NS) group, a CIH control group and a control group. CIH rats were subjected to alternating cycles of hypoxia (6%-8%O2 in N2 for 20-25 s) and normoxia (21%O2 in N2 for 2 min) every 180 s for 7 h/d. Rats in the control group were not treated. Rats in the CIH+NAC group were treated with NAC [800 mL/(kg.d)] intraperitoneal injection, and rats in the CIH+NS group were treated with NS [5 mL/(kg.d)] intraperitoneal injection. Atfer 42 day treatment, the rats were sacriifced, blood taken, and thoracic aorta cut off. hTe serum concentration of HIF-1α, ox-LDL, and PTX3 were detected by ELISA. hTe thickness of intima was taken by computer digital image analysis. Results:Vascular endothelial cell injury and detachment were found in the thoracic aorta in the CIH and the CIH+NS group. The intima in the CIH and the CIH+NS group was thicker than that in the control and the CIH+NAC group (P<0.001). The serum concentration of HIF-1α, ox-LDL, and PTX3 in the CIH and the CIH+NS group was higher than that in the control and the CIH+NAC group (P<0.001). The serum concentration of HIF-1α, ox-LDL, and PTX3 was pairwise positive correlation, and the serum concentration of ox-LDL and PTX3 was positively correlated with the thickness of intina (P<0.001). Conclusion:hTe vascular endothelial cell injury and endarterium thickening can be induced by CIH. It is an important pathway that CIH activates oxidative stress and elevates the levels of HIF-1α, ox-LDL, and PTX3.

Lysophosphatidylcholine, Oxidized Low-Density Lipoprotein and Cardiovascular Disease in Korean Hemodialysis Patients: Analysis at 5 Years of Follow-up

Although oxidized low-density lipoprotein (LDL) and lysophosphatidylcholine (LPC) have been proposed as important mediators of the atherosclerosis, the long-term contribution to the risk of cardiovascular disease (CVD) in hemodialysis patients has not been evaluated. This study investigated the relation between oxidized LDL and LPC levels with long term risk of CVD. Plasma oxidized LDL and LPC levels were determined in 69 Korean hemodialysis patients as a prospective observational study for 5 yr. During the observation period, 18 cardiovascular events (26.1%) occurred including 6 deaths among the hemodialysis patients. The low LPC level group ( 254 microM/L) (P = 0.01). However, serum levels of oxidized LDL were not significantly different between groups with and without CVD. In adjusted Cox analysis, previous CVD, (hazard ratio [HR], 5.68; 95% confidence interval [CI], 1.94-16.63, P = 0.002) and low LPC level (HR, 3.45; 95% CI, 1.04-11.42, P = 0.04) were significant independent risk factors for development of CVD. It is suggested that low LPC, but not oxidized LDL, is associated with increased risk of CVD among a group of Korean hemodialysis patients.

Association of postalimentary lipemia with atherosclerotic manifestations

We identified different lipemic and metabolic responses after the ingestion of a standardized meal by healthy adults and related them to atherosclerotic markers. Samples from 60 normolipidemic adults were collected before and after a liquid meal (40 g fat/m² body surface) at 0, 2, 4, 6, and 8 h for measurements of lipids, free fatty acids (FFA), insulin, cholesteryl ester transfer protein (CETP), autoantibodies to epitopes of oxidized LDL (oxLDL Ab), lipolytic activities, and apolipoprotein E polymorphism. Mean carotid intima-media thickness (cIMT) was determined by Doppler ultrasound. The volunteers were classified into early (N = 39) and late (N = 31) triacylglycerol (TAG) responders to the test meal. Late responders showed lower HDL cholesterol concentration at fasting and in the TAG peak, lower insulin and higher FFA concentrations compared to early responders. Multivariate regression analyses showed that mean cIMT was associated with gender (male) and age in early responders and by cholesterol levels at the 6th hour in late responders. oxLDL Ab were explained by lipoprotein lipase and negatively by hepatic lipase and oxLDL Ab (fasting period) by CETP (negative) and FFA (positive). This study is the first to identify a postalimentary insulin resistance state, combined with a reduced CETP response exclusively among late responders, and the identification of the regulators of postalimentary atherogenicity. Further research is required to determine the metabolic mechanisms described in the different postalimentary phenotypes observed in this study, as well as in different pathological states, as currently investigated in our laboratory.

Effect of oxidized low-density lipoprotein on Notchl expression and cytokine secretion in THP1 cells / 第二军医大学学报

Objective: To explore the effect of oxidized low-density lipoprotein (ox-LDL) on Notch 1 expression and cytokine secretion in human acute monocytic leukemia cell line THP1, so as to discuss the role of ox-LDL in atherosclerosis (AS). Methods: THP1 cells were stimulated with PMA to induce human macrophages, which were then exposed to ox-LDL of different concentrations. The morphological changes of the cells was observed by phase contrast microscope. The expression of Notch1 mRNA was examined by real-time quantitative PCR (RT-PCR) and protein expression was measured by Western blotting analysis in the cells. The levels of vascular cell adhesive molecule-1(VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) in supernatants were determined by ELISA. Results: The macrophages differentiated into dendritic like cells 48 h after ox-LDL treatment. Ox-LDL treatment increased Notch1 mRNA and protein expression compared with the control group. Ox-LDL also significantly increased the levels of VCAM-1 and MCP-1 in the supernatant in a dose-dependent manner (P <0.05). The best effect of ox-LDL was seen at the concentration of 50 mg/L. Conclusion: Ox-LDL stimulation can increase Notch 1 expression in THP1 cells; meanwhile, it can also promote the secretion of AS-related cytokines. The role of ox-LDL in AS might be partly mediated by Notch1.

LDL oxidada circulante y anticuerpos contra LDL oxidada según niveles de ácido úrico en mujeres con exceso de peso / Oxidized LDL and anti-oxidized LDL antibodies according uric acid levels in overweight women

Objetivo: Establecer si el aumento de ácido úrico sérico se asocia a niveles más elevados de LDL oxidada (LDLox), anticuerpos contra LDLox (anti LDLox) e índices de oxidación de la LDL, en mujeres con exceso de peso. Método: Estudio transversal que incluyó 114 mujeres con índice de masa corporal > 25 kg/m². Se determinó peso, talla, circunferencia abdominal, presión arterial, glicemia, ácido úrico, perfil lipídico, creatinina, apolipoproteína B (ApoB), LDLox, anti LDLox e insulina. Se estimó resistencia a la insulina mediante HOMA. Se calcularon índice de masa corporal, ApoB asociada a LDL, índices de oxidación de la LDL y terciles de ácido úrico. Se diagnosticó síndrome metabólico según criterios del NCEP/ATP III. Resultados: De las mujeres estudiadas, 51.8% mostró sobrepeso y el resto fueron obesas; 66.7% presentó síndrome metabólico. En el grupo con sobrepeso y en el grupo total de mujeres, sólo el índice LDLox/HDLc fue significativamente mayor en el último tercil de ácido úrico. Las concentraciones séricas de LDLox y los índices LDLox/colesterol total, LDLox/HDLc, LDLox/ApoB y LDLox/ApoB asociada a LDL fueron significativamente mayores entre las obesas ubicadas en el tercil más elevado de ácido úrico. Las concentraciones de anti LDLox y el índice LDLox/Anti LDLox no se relacionaron con ácido úrico. Los niveles séricos de ácido úrico y ApoB predijeron la elevación de la LDLox. Conclusión: El aumento del ácido úrico sérico se asoció con mayor oxidación de la LDL entre mujeres obesas, sugiriendo la importancia que podría tener el control periódico de ácido úrico en mujeres con exceso de peso.

Objective: To establish whether increased serum uric acid is associated with higher levels of oxidized LDL (oxLDL), antibodies against human oxidized LDL (oxLDL Ab) and ratios of LDL oxidation in overweight women. Methods: Cross-sectional study that included 114 women with body mass index > 25 kg/m2. We determined weight, height, waist circumference, blood pressure, glycemia, uric acid, lipid profile, creatinine, Apolipoprotein B (ApoB), oxLDL, oxLDL Ab, insulin and insulin resistance was estimated using HOMA. Body mass index, LDL-associated ApoB, rates of LDL oxidation and tertiles of uric acid were calculated. Metabolic syndrome was defined using NCEP/ATP III criteria. Results: Of the women studied 51.8% were overweight and the rest was classified as obese; 66.7% had metabolic syndrome. In the total group and overweight group, only the oxLDL/HDL cholesterol ratio was significantly higher in the last tertile of uric acid. The serum levels of circulanting oxLDL and oxLDL/cholesterol, oxLDL/HDL cholesterol, oxLDL/ApoB and oxLDL/ LDL-associated ApoB ratios were significantly higher among obese women located in the highest tertile of uric acid. Concentrations of oxLDL Ab and oxLDL/oxLDL Ab were not related to the uric acid. Serum uric acid and ApoB predicted the elevation of oxLDL. Conclusion: Increased serum uric acid was associated with more oxidation of LDL among obese women. This suggests the importance of regular monitoring of uric acid in overweight women. Prospective research should be conducted.

Determinación de autoanticuerpos contra lipoproteínas de baja densidad oxidadas y nativas en el suero de pacientes sometidos a coronariografía en el CIMEQ / Determination of auto-antibodies to native and oxidized low-density lipoproteins (LDL) in serum of patients underwent coronariography in the Medical-Surgical Research Center (MSRC)

La oxidación de las lipoproteínas de baja densidad (LDLox) es un evento importante en el desarrollo y progresión de la aterosclerosis y la respuesta inmune contra estas moléculas puede modular la aterogénesis. La relación entre los autoanticuerpos anti-LDLox y la cardiopatía isquémica (CI) es aún controversial. En el presente estudio se determinaron los valores de las IgM e IgG anti-LDLox, en 20 pacientes a quienes se les indicó una coronariografía por alguna razón en la consulta de cardiología. Se tomó como grupo control a 10 voluntarios jóvenes sanos trabajadores del Centro de Inmunología Molecular. Los niveles de anticuerpos de tipo IgM contra las LDLox no fueron diferentes entre los pacientes sin evidencia de CI y los sujetos jóvenes sanos. En cambio, los niveles de IgM anti-LDLox de estos grupos fueron estadísticamente superiores a los del grupo de pacientes con evidencia de CI. Nuestros resultados, aunque preliminares, sustentan la hipótesis de que este tipo de autoanticuerpos pudiera estar inversamente asociado con la presencia de aterosclerosis

Low-density lipoprotein (LDL) oxidation is an important event in atherosclerosis development. The relationship between oxidized LDL (oxLDL) autoantibodies and coronary artery disease (CAD) remains controversial. IgM and IgG autoantibodies to oxLDL were measured in twenty patients undergoing clinically indicated coronary angiography, and in ten young healthy volunteers from the Center of Molecular Immunology. The levels of IgM autoantibodies to oxLDL did not differ between no CAD patients and healthy subjects, but the levels of IgM autoantibodies to oxLDL of these two groups were higher compared with the one of CAD patient group. Our results, although preliminary, supports the hypothesis that this kind of Abs might be inversely associated with the presence of atherosclerosis

Auto antibodies against oxidized low density lipoproteins and lipid peroxidation in patients with essential hypertension

Lipid peroxidation has been suggested to play a key role in the oxidative modification of LDL (oxd-LDL) which stimulate the production of auto antibodies by Bcells and anti-oxd LDL antibodies are produced. These antibodies could represent a biological marker of oxidative stress and serve as markers of atherosclerosis. Essential hypertension is a major risk factor for atherosclerosis, recently border line hypertension also has been shown to be a risk factor for atherosclerosis. The aim of this study is to examine the correlation between oxd -LDL antibodies and lipid peroxidation in patient with essential hypertension. Blood samples were collected from patients with essential hypertension (n=155) and healthy individuals (n=160) levels of Malonaldihyde (MDA), Total cholesterol, Triglycerides, HDL and LDL were estimated by spectrophotometry and levels of Oxd- LDL antibodies were obtained by ELISA. Plasma levels of MDA, anti-oxdLDL antibodies, Total cholesterol and LDL Cholesterol is higher in patients than those in controls. Among patients concentration of MDA, total cholesterol and LDL cholesterol were not significantly different, however the concentration of anti-oxd LDL were higher in essential hypertensive patients (p=0.003). Significant positive correlation was observed between plasma levels of MDA, total cholesterol, LDL cholesterol and the concentration of anti-oxdLDL in patients but not in the controls. In conclusion High concentrations of anti-oxdLDL and MDA suggest an increase in oxidative stress that would contribute to the development of atherosclerosis. The observed correlation of MDA with anti-oxdLDL indicates the relationship between free radicals and atherosclerosis in essential hypertension.

Paraoxonase gene Q192R & L55M polymorphisms in Indians with acute myocardial infarction & association with oxidized low density lipoprotein.

Background & objectives: Paraoxonase (PON) is an HDL associated ester hydrolase with an ability to retard LDL oxidation in vitro by preventing lipid peroxide generation. The population variability in enzyme activity is attributed to polymorphisms in paraoxonase gene. For example, polymorphism at codon 192 and 55 of the paraoxonase gene has been reported to be associated with coronary heart disease (CAD) and diabetes among different ethnic groups. The present study looks at PON192 and 55 polymorphism among hospitalized Asian Indian patients with myocardial infarction (MI) and their association with circulating oxidized LDL and antioxidant status. Methods: One hundred and twenty four consecutive patients of acute myocardial infarction and 221 age-matched controls were recruited for the study. Oxidized LDL was measured in serum by ELISA and total antioxidant levels by the 2,2’-azino-bis-(3 ethyl benzothiozoline-6-sulfonate) (ABTS) method. Other known cardiovascular risk factors, apolipoprotein B, apolipoproteinA1, lipoprotein(a), hsCRP and homocysteine were also measured. Paraoxonase gene polymorphism at codon 192 and 55 were analyzed by PCR-RFLP. Results: Patients with MI had significantly higher oxidized LDL (P<0.05) and lower total antioxidant capacity (P<0.001) as compared to controls. Oxidized LDL correlated with total cholesterol, LDL and Apo B in patients. B allele frequency of the codon 192 polymorphism in paraoxonase gene was higher in cases as compared to controls and odds ratio of developing the MI with BB genotype versus AA genotype was 2.37, (P=0.044). Codon 55 polymorphism in paraoxonase gene was not associated with CAD. There was no difference in oxidized LDL between the different genotypes of PON192 and PON55. Interpretation & conclusions: Although PON192 polymorphism was associated with CAD, no correlation of PON192 or 55 polymorphism was found with oxidized LDL suggesting that presence of other antioxidant factors may be of equal importance in preventing LDL oxidation.

Enhanced uptake of human mesangial cell line to oxidized low density lipoprotein stimulated by interleukin-1β partly through the lectin-like oxidized low-density lipoprotein receptor pathway / 中华肾脏病杂志

Objective To analysis if intedeukin-1β (IL-1β) can regulate human mesangial cells (HMC) to uptake oxidized low density lipoprotein (Ox-LDL) and if the effect of IL-lβ be changed through the lectin-like oxidized low-density lipoprotein receptor 1 (LOX-l)pathway. Methods The uptake of HMC to Ox-LDL stimulated by IL-1β was observed using Oil Red "O" and flow cytometry. The level of LOX-1 in HMC induced by IL-1β and Ox-LDL was examined using real-time PCR and Western blotting. Results Uptake of Ox-LDL and Dil-Ox-LDL by HMC was up-regulated upon stimulation with IL-1β in a dose- and time-dependent manner. Intracellular mean fluorescence density of Dil-Ox-LDL with LOX-1 blocker in IL-1β stimulation group was decreased compared to that without blocker. The peak level of LOX-1 mRNA reached after 6 h of stimulation and was as high as 6.87-fold of control. IL-1β could induce LOX-1 mRNA expression in a dose-dependent manner. Treated with 10 μg/L IL-1β for 12 h, the upregulation effect on LOX-1 mRNA was as high as 6.57-fold of control. IL-1β could induce LOX-1 protein expression in a time- and dose-dependent manner. The peak level of LOX-1 protein reached after 24 h of stimulation of 5 μg/L IL-1β and was as high as 1.88-fold of control. Treated with 10 μg/L IL-1β for 24 h, the up-regulation effect on LOX-1 protein reached peak and was as high as 2.57-fold of control. IL-1β could induce LOX-1 mRNA and protein expression in a dosedependent manner. Conclusion The expression of LOX-1 can be up-regulated by IL-1β in a dose-dependent manner and the enhanced uptake of HMC to Ox-LDL stimulated by IL-1β partly through the LOX-1 pathway, which means the dyslipidemia of HMC can be enhanced by inflammatory cytokines.

Synthetic nanoemulsion resembling a protein-free model of 7-ketocholesterol containing low density lipoprotein: In vitro and in vivo studies

7-ketocholesterol (7-KC) differs from cholesterol by a functional ketone group at C7. It is an oxygenated cholesterol derivative (oxysterol), commonly present in oxidized low-density lipoprotein (LDL). Oxysterols are generated and participate in several physiologic and pathophysiologic processes. For instance, the cytotoxic effects of oxidized LDL have been widely attributed to bioactive compounds like oxysterols. The toxicity is in part due to 7-KC. Here we aimed to demonstrate the possibility of incorporating 7-KC into the synthetic nanoemulsion LDE, which resembles LDL in composition and behavior. This would provide a suitable artificial particle resembling LDL to study 7-KC metabolism. We were able to incorpórate 7-KC in several amounts into LDE. The incorporation was evaluated and confirmed by several methods, including gel filtration chromatography, using radiolabeled lipids. The incorporation did not change the main lipid composition characteristics of the new nanoparticle. Particle sizes were also evaluated and did not differ from LDE. In vivo studies were performed by injecting the nanoemulsion into mice. The plasma kinetics and the targeted organs were the same as described for LDE. Therefore, 7-KC-LDE maintains composition, size and some functional characteristics of LDE and could be used in experiments dealing with 7-ketocholesterol metabolism in lipoproteins.

Correlation of oxidized low-density lipoprotein and lectin-like oxidized low-density lipoprotein receptor-1 with pre-eclampsia / 中华妇产科杂志

Objective To investigate the role of oxidized low-density lipoprotein (oxLDL) and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-I) in pre-ecalmpsia. Methods From June 2007 to January 2008,73 women with pre-eelampsia who delivered in the Department of Obstetrics, Affiliated Hospital of Qingdao University Medical College,were recruited, including 35 women with mild pre-eclampsia (MPE group) and 38 women with severe pre-eclampsia(SPE group). And 45 healthy pregnant women were taken as control group. Enzyme-linked immunosorbent assay (ELISA) was used to measure the plasma concentrations of oxLDL in these women. Semiquantitative RT-PCR and Western blot were used to investigate the expression of LOX-1 mRNA and protein in placenta. The expression of caspase-3 mRNA in placenta was determined using Semiquantitative RT-PCR. Results (1) The plasma concentrations of oxLDL in MPE group ( 0.42 ± 0.11 ) mg/L, SPE group ( 0.68 ± 0.12 ) mg/L, were significantly higher compared with control group (0.35 ± 0.14 )mg/L( P < 0.01 ) and the concentrations of oxLDL in MPE group were significantly higher compared with SPE group (P<0.01 ). (2) The expression of LOX-1 mRNA in placenta of MPE group(0.70 ±0.10) and SPE group(0.84 ±0.08) were significantly higher than that in control group(0.58 ± 0.11 ) ( P<0.01 ) and the expression of LOX-1 mRNA in MPE group was significantly higher than that of SPE group (P<0.01 ). (3) The expression of LOX-1 protein in placenta of MPE group (0.79±0.15 )and SPE group(0.90±0.12) were significantly higher compared with control group(0.68 ±0.11)( P<0.01 ), while the expression of LOX-1 protein of MPE group was significantly higher compared with SPE group (P <0.01 ). (4) The expression of caspase-3 mRNA in placenta of MPE group(3.82± 0.18) and SPE group(5.39±0.14) were significantly higher than that in control group(2.19±0.20) (P <0.01 ), and the expression of caspase-3 mRNA in MPE group was significantly higher than that of SPE group (P<0.01 ). (5) In pre-eclampsia groups, the levels of LOX-1 mRNA in placenta were positively correlated with the plasma concentrations of ox LDL ( r=0.93, P<0.05 ), and caspase-3 mRNA expression were positively correlated with the expression of LOX-1 mRNA in placenta( r=0.84, P<0.05). Conclusion Increased levels of oxLDL in plasma may induce excess expression of LOX-1 in placenta, which may be involved in the pathophysiological processes of pre-eclampsia.

Oxidized Low-density Lipoprotein- and Lysophosphatidylcholine-induced Ca2+ Mobilization in Human Endothelial Cells

The effects of oxidized low-density lipoprotein (OxLDL) and its major lipid constituent lysophosphatidylcholine (LPC) on Ca2+ entry were investigated in cultured human umbilical endothelial cells (HUVECs) using fura-2 fluorescence and patch-clamp methods. OxLDL or LPC increased intracellular Ca2+ concentration ([Ca2+]i), and the increase of [Ca2+]i by OxLDL or by LPC was inhibited by La3+ or heparin. LPC failed to increase [Ca2+]i in the presence of an antioxidant tempol. In addition, store-operated Ca2+ entry (SOC), which was evoked by intracellular Ca2+ store depletion in Ca2+-free solution using the sarcoplasmic reticulum Ca2+ pump blocker, 2, 5-di-t-butyl-1, 4-benzohydroquinone (BHQ), was further enhanced by OxLDL or by LPC. Increased SOC by OxLDL or by LPC was inhibited by U73122. In voltage-clamped cells, OxLDL or LPC increased [Ca2+]i and simultaneously activated non-selective cation (NSC) currents. LPC-induced NSC currents were inhibited by 2-APB, La3+ or U73122, and NSC currents were not activated by LPC in the presence of tempol. Furthermore, in voltage-clamped HUVECs, OxLDL enhanced SOC and evoked outward currents simultaneously. Clamping intracellular Ca2+ to 1 micrometer activated large-conductance Ca2+-activated K+ (BKCa) current spontaneously, and this activated BKCa current was further enhanced by OxLDL or by LPC. From these results, we concluded that OxLDL or its main component LPC activates Ca2+-permeable Ca2+-activated NSC current and BKCa current simultaneously, thereby increasing SOC.