Aerobic exercise training enhances the in vivo cholesterol trafficking from macrophages to the liver independently of changes in the expression of genes involved in lipid flux in macrophages and aorta.

BACKGROUND: Regular exercise prevents and regresses atherosclerosis by improving lipid metabolism and antioxidant defenses. Exercise ameliorates the reverse cholesterol transport (RCT), an antiatherogenic system that drives cholesterol from arterial macrophages to the liver for excretion into bile and feces. In this study we analyzed the role of aerobic exercise on the in vivo RCT and expression of genes and proteins involved in lipid flux and inflammation in peritoneal macrophages, aortic arch and liver from wild type mice. METHODS: Twelve-week-old male mice were divided into sedentary and trained groups. Exercise training was performed in a treadmill (15 m/min, 30 min/day, 5 days/week). Plasma lipids were determined by enzymatic methods and lipoprotein profile by fast protein liquid chromatography. After intraperitoneal injection of J774-macrophages the RCT was assessed by measuring the recovery of (3)H-cholesterol in plasma, feces and liver. The expression of liver receptors was determined by immunoblot, macrophages and aortic mRNAs by qRT-PCR. (14)C-cholesterol efflux mediated by apo A-I and HDL2 and the uptake of (3)H-cholesteryl oleoyl ether ((3)H-COE)-acetylated-LDL were determined in macrophages isolated from sedentary and trained animals 48 h after the last exercise session. RESULTS: Body weight, plasma lipids, lipoprotein profile, glucose and blood pressure were not modified by exercise training. A greater amount of (3)H-cholesterol was recovered in plasma (24 h and 48 h) and liver (48 h) from trained animals in comparison to sedentary. No difference was found in (3)H-cholesterol excreted in feces between trained and sedentary mice. The hepatic expression of scavenger receptor class B type I (SR-BI) and LDL receptor (B-E) was enhanced by exercise. We observed 2.8 and 1.7 fold rise, respectively, in LXR and Cyp7a mRNA in the liver of trained as compared to sedentary mice. Macrophage and aortic expression of genes involved in lipid efflux was not systematically changed by physical exercise. In agreement, (14)C-cholesterol efflux and uptake of (3)H-COE-acetylated-LDL by macrophages was similar between sedentary and trained animals. CONCLUSION: Aerobic exercise in vivo accelerates the traffic of cholesterol from macrophages to the liver contributing to prevention and regression of atherosclerosis, independently of changes in macrophage and aorta gene expression.

Persistent Effect of Advanced Glycated Albumin Driving Inflammation and Disturbances in Cholesterol Efflux in Macrophages.

Advanced glycated albumin (AGE-albumin) impairs cholesterol efflux and contributes to inflammation in macrophages. The current study evaluated: (1) the persistence of the deleterious effect of AGE-albumin in cholesterol efflux and in inflammation, and (2) how metabolic control in diabetes mellitus (DM) contributes to attenuate the deleterious role of AGE-albumin in macrophage cholesterol homeostasis. Methods: AGE-albumin was produced in vitro or isolated from uncontrolled DM subjects' serum before (bGC) and after improved glycemic control (aGC). Albumin samples were incubated with bone marrow-derived macrophages and 14C-cholesterol efflux or LPS- induced cytokine secretion were determined immediately, or after cell resting in culture media alone. The ABCA-1 degradation rate was determined after cell incubation with cycloheximide, and ABCA1 protein level by immunoblot. Oil Red O staining was used to assess intracellular lipid accumulation. Results: A persistent effect of AGE-albumin was observed in macrophages in terms of the secretion of inflammatory cytokines and reduced cholesterol efflux. HDL-mediated 14C-cholesterol efflux was at least two times higher in macrophages treated with aCG-albumin as compared to bGC-albumin, and intracellular lipid content was significantly reduced in aGC-albumin-treated cells. As compared to bGC-albumin, the ABCA-1 protein content in whole cell bulk was 94% higher in aCG-albumin. A 20% increased ABCA-1 decay rate was observed in macrophages treated with albumin from poorly controlled DM. AGE-albumin has a persistent deleterious effect on macrophage lipid homeostasis and inflammation. The reduction of AGEs in albumin ameliorates cholesterol efflux.

AGE-albumin enhances ABCA1 degradation by ubiquitin-proteasome and lysosomal pathways in macrophages.

BACKGROUND AND AIMS: Advanced glycation end products (AGEs) induce cellular oxidative/endoplasmic reticulum stress and inflammation. We investigated its underlying mechanisms for atherogenesis focusing on regulation of ABCA1 protein decay in macrophages. METHODS: The ABCA1 decay rate was evaluated in macrophages after treatment with LXR agonist and by incubation with control (C) or AGE-albumin concomitant or not with cycloheximide, MG-132, ammonium chloride and calpain inhibitors were utilized to inhibit, respectively, proteasome, lysosome and ABCA1 proteolysis at cell surface. ABCA1 was determined by immunoblot and the protein decay rate calculated along time by the slope of the linear regression. Ubiquitination level was determined in ABCA1 immunoprecipitated from whole cell lysate or bulk cell membrane. AGE effect was also analyzed in THP-1 cells transfected with siRNA-RAGE. Carboxymethyllysine (CML) and pyrraline (PYR) were determined by LC/MS. One-way ANOVA and Student t test were utilized to compare results. RESULTS: CML and PYR-albumin were higher in AGE-albumin as compared to C. AGE-albumin reduced ABCA1 in J774 and THP-1 macrophages (20-30%) and induced a higher ABCA1 ubiquitination and a faster protein decay rate that was dependent on the presence of AGE during the kinetics of measurement in the presence of cycloheximide. Proteasomal inhibition restored and lysosomal inhibition partially recovered ABCA1 in cells treated with AGE-albumin. Calpain inhibition was not able to rescue ABCA1. RAGE knockdown prevented the reduction in ABCA1 elicited by AGE. CONCLUSIONS: AGE-albumin diminishes ABCA1 by accelerating its degradation through the proteasomal and lysosomal systems. This may increase lipid accumulation in macrophages by diminishing cholesterol efflux via RAGE signaling contributing to atherosclerosis in diabetes mellitus.

Glycated albumin induces lipid infiltration in mice aorta independently of DM and RAS local modulation by inducing lipid peroxidation and inflammation.

AIMS: Advanced glycated albumin (AGE-albumin) adversely impairs macrophage lipid homeostasis in vitro, which may be prevented by angiotensin receptor blockers. In vivo studies are inconclusive whether AGE-albumin itself plays important role in early-stage atherogenesis. We aimed at investigating how AGE-albumin by itself drives atherosclerosis development in dyslipidemic non-diabetic mice and if its effects are due to the activation of renin-angiotensin system in the arterial wall and the expression of genes and proteins involved in lipid flux. METHODS AND RESULTS: Murine albumin glycation was induced by incubation with 10mM glycolaldehyde and C-albumin with PBS alone. Twelve-week-old-male apoE knockout mice were submitted to a daily IP injection of control (C) or AGE-albumin (2mg/mL) during 30days with or without losartan (LOS: 100mg/L; C+LOS and AGE+LOS). Aortic arch was removed, and gene expression was determined by RT-PCR and protein content by immunofluorescence. Plasma lipid and glucose levels were similar among groups. Systolic blood pressure was similarly reduced in both groups treated with LOS. In comparison to C-albumin, aortic lipid infiltration was 5.3 times increased by AGE-albumin, which was avoided by LOS. LOS prevented the enhancement induced by AGE-albumin in Ager, Tnf and Cybb mRNA levels but did not reduce Olr1. Nfkb and Agt mRNA levels were unchanged by AGE-albumin. LOS similarly reduced Agtr1a mRNA level in both C and AGE-albumin groups. In AGE-albumin-treated mice, immunofluorescence for carboxymethyl-lysine, 4-hydroxynonenal and RAGE was respectively, 4.8, 2.6 and 1.7 times enhanced in comparison to C-albumin. These increases were all avoided by LOS. CONCLUSIONS: AGE-albumin evokes a pre-stage of atherogenesis in dyslipidemic mice independently of the presence of diabetes mellitus or modulation in the RAS in part by the induction of lipid peroxidation and inflammation.

Albumina modificada por glicação avançada sensibiliza macrófagos à inflamação prejudicando o transporte reverso de colesterol e a atividade anti-inflamatória da HDL / Advanced glycated albumin primes macrophages to an inflammatory response that reduces reverse cholesterol transport and impairs the HDL anti-inflammatory properties

No diabete melito, produtos de glicação avançada (AGE) reduzem o efluxo de colesterol celular o que agrava o desenvolvimento da aterosclerose. Neste estudo, investigou-se o papel da albumina modificada por glicação avançada (albumina-AGE) sobre a sensibilização de macrófagos à resposta inflamatória e o impacto da secreção de citocinas, quimocinas e moléculas de adesão sobre o efluxo de colesterol mediado por apolipoproteína A-I e subfrações de HDL. Além disso, determinou-se a capacidade da HDL em modular a resposta inflamatória em macrófagos tratados com albumina-AGE. Macrófagos de peritônio de camundongo foram tratados com ou sem sobrecarga de colesterol, na presença de 2 mg/mL de albumina-controle (albumina-C) ou albumina-AGE, por 72 h, seguindo-se de incubação, por 24 h, com calgranulina S100B (20 g/mL) ou lipopolissacarídeo (LPS; 1 g/mL). Em comparação com albumina-C, a albumina-AGE, isenta em endotoxinas, isoladamente não alterou a secreção de citocinas em macrófagos. No entanto, a albumina-AGE sensibilizou macrófagos não enriquecidos em colesterol a uma maior secreção de interleucina 6 (IL-6), fator de necrose tumoral alfa (TNF-), proteína quimoatraente de monócitos 1 (MCP-1), interlucina 1 beta (IL-1) e molécula de adesão celular vascular 1 (VCAM-1) após estimulação com S100B ou LPS, o que foi potencializado pela sobrecarga de colesterol celular. Em macrófagos não estimulados, o meio condicionado, advindo das incubações de células com albumina-AGE e S100B (meio enriquecido em citocinas), reduziu o efluxo de 14C-colesterol mediado por apoA-I, HDL2 e HDL3 em, respectivamente, 23%, 43% e 20%, em comparação com células incubadas com meio isolado do tratamento com albumina-C e S100B. De forma similar, o efluxo de 14C-colesterol mediado por apoA-I, HDL2 e HDL3 foi reduzido em macrófagos tratados com meio advindo de incubações com albumina-AGE e LPS, respectivamente, 37%, 47% e 8,5% em comparação ao tratamento com albumina-C e LPS. Em macrófagos tratados com...

In diabetes mellitus, advanced glycation end products (AGE) reduces the cholesterol efflux from cells, which aggravates the development of atherosclerosis. In this study, we investigated the role of advanced glycated albumin (AGE-albumin) on macrophage inflammatory response and the impact of cytokines, chemokines and adhesion molecules secretion on cholesterol efflux mediated by apolipoprotein A-I (apoA-I) and HDL subfractions. Furthermore, the HDL ability in modulating inflammatory response in macrophages treated with AGE-albumin was also determined. Mouse peritoneal macrophages previously enriched or not with cholesterol were treated in the presence of 2 mg/mL of control-albumin (C-albumin) or AGE-albumin, for 72 h, followed by incubation, for 24 h, with S100B calgranulin (20 g/mL) or lipopolysaccharide (LPS; 1 g/mL). In comparison to free endotoxin-C-albumin, AGE-albumin, by itself did not alter cytokine secretion by macrophages. However, AGE-albumin primed non-cholesterol enriched macrophages to a higher secretion of interleukin -6 (IL-6), tumor necrosis factor alpha (TNF-), monocyte chemotactic protein 1 (MCP-1), interleukin 1 beta (IL-1) and vascular cell adhesion molecule 1 (VCAM-1) after stimulation with S100B or LPS, which was potentiated by cell cholesterol overload. In non-stimulated macrophages, conditioned medium, derived from incubation with AGE-albumin and S100B (cytokine enriched-medium), reduced the 14C-cholesterol efflux mediated by apoA-I, HDL2 and HDL3 in, respectively, 23%, 43% and 20%, in comparison to cells incubated with conditioned medium isolated from treatment with C-albumin and S100B. Similarly, 14C-cholesterol efflux mediated by apoA-I, HDL2 and HDL3 was reduced in macrophages treated with medium derived from incubation with AGE-albumin and LPS, respectively, 37%, 47% and 8,5% in comparison to treatment with C-albumin and LPS. In macrophages treated with C-albumin and S100B, previous incubation with HDL reduced the secretion of...

Aleitamento materno: quando o álcool pode influenciar na saúde do bebê? / Breast-feeding to which extent alcohol can affect the baby's health?

Objetivos: rever literatura científica acerca da teratogenicidade do álcool sobre o bebê durante o aleitamento materno. Fontes pesquisadas: revisão bibliográfica realizada no Sistema MEDLINE (Index Medicus) cruzando os descritores álcool e aleitamento materno...

Objectives: to review the scientific literature about the teratogenicity of alcohol on the baby during breast-feeding. Researched sources: bibliographic review carried out in the MED_LINE (Index Medicus) System, crossing the descriptors alcohol and breast-feeding...