Impaired high-density lipoprotein function and endothelial barrier stability in severe anaphylaxis.

BACKGROUND: Growing evidence demonstrates the importance of high- and low-density lipoprotein cholesterol in certain immune and allergy-mediated diseases. OBJECTIVE: This study aimed to evaluate levels of high- and low-density lipoprotein cholesterol and apolipoproteins A1 and B in sera from a cohort of patients presenting with hypersensitivity reactions. We further assessed the function of high-density lipoprotein particles as well as their involvement in the molecular mechanisms of anaphylaxis. METHODS: Lipid profile determination was performed in paired (acute and baseline) serum samples from 153 patients. Thirty-eight experienced a non-anaphylactic reaction and 115 had an anaphylactic reaction (88 moderate and 27 severe). Lecithin cholesterol acyl transferase activity was assessed in patient sera, and we also evaluated macrophage cholesterol efflux in response to the serum samples. Last, the effect of anaphylactic-derived high-density lipoprotein (HDL) particles on the endothelial barrier was studied. Detailed methods are provided in the Methods section in this article's Online Repository available at www.jacionline.org. RESULTS: Serum samples from severe anaphylactic reactions show statistically significant low levels of HDL cholesterol, low-density lipoprotein cholesterol, and apolipoproteins A1 and B, which points to their possible role as biomarkers. Specifically, HDL particles play a protective role in cardiovascular diseases. Using functional human serum cell assays, we observed impaired capacity of apolipoprotein B-depleted serum to induce macrophage cholesterol efflux in severe anaphylactic reactions. In addition, purified HDL particles from human anaphylactic sera failed to stabilize and maintain the endothelial barrier. CONCLUSION: These results encourage further research on HDL functions in severe anaphylaxis, which may lead to new diagnostic and therapeutic strategies.

Apolipoproteins and Lipoproteins in Health and Disease 2.0.

Cardiovascular diseases (CVDs) remain the leading cause of mortality worldwide, accounting for 32% of global deaths, according to the World Health Organization (WHO) [...].

Lysyl oxidase expression in smooth muscle cells determines the level of intima calcification in hypercholesterolemia-induced atherosclerosis. / La expresión de la lisil oxidasa en las células musculares lisas determina el nivel de calcificación de la íntima en la aterosclerosis inducida por hipercolesterolemia.

INTRODUCTION: Cardiovascular calcification is an important public health issue with an unmeet therapeutic need. We had previously shown that lysyl oxidase (LOX) activity critically influences vascular wall smooth muscle cells (VSMCs) and valvular interstitial cells (VICs) calcification by affecting extracellular matrix remodeling. We have delved into the participation of LOX in atherosclerosis and vascular calcification, as well as in the mineralization of the aortic valve. METHODS: Immunohistochemical and expression studies were carried out in human atherosclerotic lesions and experimental models, valves from patients with aortic stenosis, VICs, and in a genetically modified mouse model that overexpresses LOX in CMLV (TgLOXCMLV). Hyperlipemia and atherosclerosis was induced in mice through the administration of adeno-associated viruses encoding a PCSK9 mutated form (AAV-PCSK9D374Y) combined with an atherogenic diet. RESULTS: LOX expression is increased in the neointimal layer of atherosclerotic lesions from human coronary arteries and in VSMC-rich regions of atheromas developed both in the brachiocephalic artery of control (C57BL/6J) animals transduced with PCSK9D374Y and in the aortic root of ApoE-/- mice. In TgLOXCMLV mice, PCSK9D374Y transduction did not significantly alter the enhanced aortic expression of genes involved in matrix remodeling, inflammation, oxidative stress and osteoblastic differentiation. Likewise, LOX transgenesis did not alter the size or lipid content of atherosclerotic lesions in the aortic arch, brachiocephalic artery and aortic root, but exacerbated calcification. Among lysyl oxidase isoenzymes, LOX is the most expressed member of this family in highly calcified human valves, colocalizing with RUNX2 in VICs. The lower calcium deposition and decreased RUNX2 levels triggered by the overexpression of the nuclear receptor NOR-1 in VICs was associated with a reduction in LOX. CONCLUSIONS: Our results show that LOX expression is increased in atherosclerotic lesions, and that overexpression of this enzyme in VSMC does not affect the size of the atheroma or its lipid content, but it does affect its degree of calcification. Further, these data suggest that the decrease in calcification driven by NOR-1 in VICs would involve a reduction in LOX. These evidences support the interest of LOX as a therapeutic target in cardiovascular calcification.

Efecto de la expresión de la PTEC, el gemfibrozilo y la rosiglitazona en el transporte inverso de colesterol desde macrófagos a heces in vivo / The effect of human CETP activity, gemfibroziland rosiglitazone on macrophage-specific reverse cholesterol transport in vivo

Introducción. La expresión de PTEC humana enratones transgénicos reduce el colesterol de las lipoproteínas de alta densidad (cHDL) y aumenta la susceptibilidad a la arteriosclerosis. Por otro lado, el gemfibrozilo, uno de los fibratos más utilizados en clínica, y la rosiglitazona aumentan el cHDL y reducen la susceptibilidad a la arteriosclerosis en modelos murinos. El objetivo principal de este estudio es evaluar el efecto de la expresión de la PTEC humana, el gemfibrozilo y la rosiglitazona en el transporte inverso de colesterol(TIC) específico de macrófagos. Materiales y método. Para determinar el TIC específico de macrófagos se aplicó inyección intraperitoneal de macrófagos P388D1 marcados con 3H-colesterol en ratones controles (C57BL/6) y ratones transgénicos de PTEC humana. Este mismo proceso se realizó en ratones transgénicos de apoA-I humana (h) que recibieron una dosis diaria por vía oral de gemfibrozilo (625 mg/kg) orosiglitazona (10 mg/kg) durante 17 días y se los comparó con los que recibieron la solución vehículo. A las 48 h, se sacrificó a los animales y se determinó el 3H-colesterol en plasma, hígado y heces. Resultados. Los ratones transgénicos de PTEC humana presentaron una disminución significativa de cHDL en plasma respecto a los ratones controles. El gemfibrozilo incrementó el colesterol total y el cHDL en los ratones transgénicos deapoA-Ih. Sin embargo, ni la expresión de PTEC humana ni los tratamientos farmacológicos alteraron la excreción fecal de colesterol y ácidos biliares. No se encontraron diferencias significativas en el TIC de 3H-colesterol desde los macrófagos P388D1 a heces en los diferentes grupos experimentales. Conclusiones. Ni la expresión de PTEC humana en ratones transgénicos ni el tratamiento congemfibrozilo o rosiglitazona en ratones transgénicos de apoA-Ih modifican el transporte inverso de colesterol especifico de macrófagos in vivo (AU)

Background. Human CETP expression in micereduces cholesterol from high density lipoprotein HDLc) and increases atherosclerosis susceptibility. On the other hand, gemfibrozil, one of the most used fibrates in clinical practice, and rosiglitazone, increase HDLc and reduce the atherosclerotic susceptibility in mouse models of atherosclerosis. The main aim of this study was to evaluate the effect of human CETP expression, and the effect of gemfibrozil or rosiglitazone treatment on one of the most important HDL anti-atherogenic properties, the macrophage-specific reverse cholesterol transport (RCT).Materials and method. To determinate the macrophage-specific RCT, [3H]cholesterol-labelledP388D1 macrophages were injected intraperitoneally into control mice (C57BL/6) and into human CETP transgenic mice. We performed the same procedure in human apoA-I transgenic mice treated during 17 days with an oral daily gavage dose of gemfibrozil (625 mg/kg),rosiglitazone (10 mg/kg) or vehicle solution. At 48h, the mice were euthanized and [3H]cholesterol in plasma, liver and faeces were measured. Results. Human CETP transgenic mice showed decreased HDLc compared to control mice. Human apoA-I transgenic mice showed an increase in total cholesterol and HDLc when treated with gemfibrozil, but not with rosiglitazone. Neither the human CETP activity, nor either of the two pharmacological treatments altered faecal cholesterol or bile acid excretion. Furthermore, the[3H]tracer detected in liver, faecal cholesterol and bile acid was not significantly different in any of the animal groups. Conclusions. Neither human CETP expression intransgenic mice, nor treatment with gemfibrozil orrosiglitazone in human apoA-I transgenic micemodified macrophage-specific reverse cholesterol transport (AU)

Análisis del proteoma hepático de ratones transgénicos de apo A-II humana: identificación de proteínas potencialmente implicadas en la regulación del metabolismo de triglicéridos y la respuesta a la insulina / Analysis of the liver proteome of human apolipoprotein A-II transgenic mice: identification of proteins potentially involved in the regulation of triglyceride metabolism and insulin response

Introducción. La función de la apolipoproteína A-II (apo A-II) en el metabolismo lipoproteico y su relación con la arteriosclerosis es poco conocida. Los estudios realizados en humanos y ratones modificados genéticamente han demostrado un efecto directo de la apo A-II en el metabolismo de los triglicéridos y los ácidos grasos libres (AGL) y la sensibilidad a la insulina. El objetivo principal de este estudio es la identificación de proteínas diferencialmente expresadas en el hígado de ratones transgénicos de apo A-II humana (h) y su potencial relación con el metabolismo de los triglicéridos y la glucosa. Material y métodos. Se realizaron estudios metabólicos de las lipoproteínas ricas en triglicéridos, la betaoxidación hepática y la prueba de tolerancia a la glucosa en ratones transgénicos de apo A-IIh y en controles en situación de ayunas y tras una carga oral de aceite de oliva. Los cambios en el perfil de expresión proteica se analizaron mediante el análisis comparativo de geles bidimensionales y la identificación de proteínas mediante espectrometría de masas MALDI-TOF. Resultados. Los ratones transgénicos de apo A-IIh presentaban un incremento del colesterol y los triglicéridos de las lipoproteínas que contienen apo B, hipertrigliceridemia aumentada tras la carga oral de ácido oleico, así como un aclaramiento acelerado de la glucosa tras la prueba de sobrecarga de glucosa. Estos cambios estaban asociados a una reducción en el catabolismo de las lipoproteínas ricas en triglicéridos y la tasa de betaoxidación hepática, pero sin cambios significativos en la actividad de la lipoproteína lipasa. De las más de 1.000 manchas resueltas en el rango pH 3 a 10, se identificaron 55 alteraciones significativas en los ratones transgénicos en comparación con los ratones controles, 16 de las cuales estaban relacionadas directamente con el metabolismo de los AGL y los carbohidratos. Conclusiones. La sobreexpresión apo A-IIh en ratones transgénicos induce hipertrigliceridemia posprandial debido, al menos en parte, a un defecto en el catabolismo de las lipoproteínas ricas en triglicéridos. La aproximación proteómica nos ha permitido detectar y caracterizar diferencias en el proteoma hepático de los ratones transgénicos de apo A-IIh y establecer proteínas potencialmente involucradas en el metabolismo de los AGL. Se requieren más estudios bioquímicos y moleculares para investigar el significado funcional de los cambios encontrados (AU)

Introduction. The role of apolipoprotein A-II (apo A-II) in lipoprotein metabolism and its relationship with atherosclerosis is poorly understood. Several studies both in humans and genetically modified mice have shown a direct effect of apo A-II on triglyceride and free fatty acid (FFA) metabolism and on insulin sensitivity. The aim of this study was to identify the proteins differentially expressed in the livers of human apo A-II transgenic mice and their potential relationship with triglyceride and glucose metabolism. Matherial and methods. Metabolic studies of triglyceride-rich lipoproteins, liver beta-oxidation and the glucose tolerance test were conducted in C57BL/6 control mice and human apo A-II transgenic mice in both fasting and postprandial states. The changes in protein expression patterns were determined by analysis of two-dimensional polyacrylamide gel electrophoresis while protein identification was performed by mass spectrometry (MALDI-TOF). Results. Human apo A-II transgenic mice showed an increase in cholesterol and triglycerides from apo B-containing lipoproteins, a higher response after oral fat test with oleic acid and higher glucose clearance after the glucose test. These changes were associated with a reduction in the clearance of triglyceride-rich lipoproteins and in the rate of liver beta-oxidation, but there were no significant changes in lipoprotein lipase activity. Within the pH 3-10 range, 55 out of more than 1,000 spots were identified to be significantly altered in human apo A-II transgenic mice compared with control mice, and 16 of these spots were directly related with FFA and carbohydrate metabolism. Conclusions. Overexpression of human apo A-II in transgenic mice induces postprandial hypertriglyceridemia. This finding is at least partly due to reduced catabolism of triglyceride-rich lipoproteins. We have been able to detect and characterize differences in the liver proteome of human apo A-II transgenic mice and to identify proteins potentially related to FFA metabolism. Further biochemical and molecular studies are required to investigate the functional significance of the changes found (AU)