Normal endothelial function in carriers of the apolipoprotein A-IMilano mutant despite low HDL-cholesterol levels

Carriers of the apolipoprotein A-IMilano (apoA-IM) mutant show severe reductions in the plasma concentration of antiatherogenic HDL but do not present with preclinical atherosclerosis and premature CHD. Aim of the present study was to investigate endothelial function in A-IM carriers, since low HDL-C levels have been associated with features of endothelial dysfunction. Plasma concentrations of soluble cell adhesion molecules (sCAMs) and forearm arterial compliance (FAC) during reactive hyperemia were evaluated in 21 A-IM carriers, 21 healthy subjects with low HDL-C, and 42 controls. Low HDL-C subjects had significantly higher plasma sCAM levels than controls (sVCAM-1: 656.3\ub149.3 vs 502.6\ub125.5 ng/ml; sICAM-1: 335.6\ub121.5 vs 267.0\ub18.9 ng/ml; sE-selectin: 62.9\ub14.1 vs 47.9\ub13.0 ng/ml); on the contrary, no differences were detected between A-IM carriers (sVCAM-1: 550.6\ub132.1 ng/ml; sICAM-1: 309.8\ub126.9 ng/ml; sE-selectin: 52.3\ub14.3 ng/ml) and controls. Low HDL-C subjects had lower FAC than controls, while no differences were detected between A-IM carriers and controls. These results suggest that HDL from A-IM carriers may be more efficient than control HDL in modulating endothelial function. To test this hypothesis, plasma HDL were isolated from 6 A-IM carriers and 6 controls, and their ability to inhibit VCAM-1 expression and to induce eNOS was tested in cultured endothelial cells. A-IM HDL were two times more effective than control HDL in reducing TNFalpha-induced VCAM-1 expression; the inhibition occurred at a transcriptional level, as demonstrated by RT-PCR. In addition, cells exposed to A-IM HDL showed higher expression of eNOS than cells treated with control HDL. In conclusion, despite the very low HDL-C levels, A-IM carriers do not display features of endothelial dysfunction, such as the increase of circulating sCAM levels and the impairment of arterial compliance, probably because of a superior ability of A-IM HDL to protect the endothelium

Oxidized low density lipoprotein suppresses expression of inducible cyclooxygenase in human macrophages

Atherogenesis involves several aspects of chronic inflammation and wound healing. Indeed, the atheroma is considered a special case of tissue response to injury. Injurious stimuli may include lipoproteins trapped within lesions where protein and lipid moieties have undergone chemical modifications. We have studied the effect of oxidized low density lipoproteins (ox-LDL) on inducible cyclooxygenase (Cox-2) in human monocyte-derived macrophages exposed to bacterial lipopolysaccharide (LPS). Levels of both Cox-2 and constitutive cyclooxygenase (Cox-1) were assessed using Western blot analysis. Prior incubation of macrophages with ox-LDL resulted in a strong inhibition of Cox-2 induced by LPS, without effect on Cox-1. The inhibitory effect was dependent on ox-LDL concentration and its onset was early in time (already detectable 1 hour after macrophage exposure to ox-LDL). Native LDL, and other forms of modified LDL, were without effect. The inhibition was dependent on endocytosis of ox-LDL and could be reproduced using the lipid extract from ox-LDL. Lysophosphatidylcholine, 7beta-hydroxycholesterol, and 7-oxocholesterol failed to mimic the inhibition, but oxidized arachidonic acid-containing phospholipids, produced by autoxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, markedly inhibited Cox-2. The observation that ox-LDL downregulates Cox-2 in human macrophages may explain the fact that, within atheromata, the transformation of macrophages into foam cells results in attenuation of the inflammatory response, thus contributing to progression of atherogenesis

Data for proteomic analysis of human monocyte-derived macrophages

This data article is referred to the research article entitled Human monocyte-derived macrophages are heterogeneous: proteomic profile of different phenotypes by Eligini et al. Eligini S., Brioschi M., Fiorelli S., Tremoli E., Banfi C., Colli S. Human monocyte-derived macrophages are heterogeneous: proteomic profile of different phenotypes. J. Proteomics 124, 2015, 112-123. Macrophages obtained in vitro from blood monocytes are largely used as surrogate model of tissue macrophages that are heterogeneous and not easy to obtain and handle. Under spontaneous differentiation in vitro, monocyte-derived macrophages (MDMs) display two dominant subsets (round and spindle) that show different transcriptional, antigenic, and functional profiles mimicking, at least in part, the heterogeneity of tissue macrophages. This article reports the nano-LC-MS(E) analysis of the proteome of round and spindle MDMs allowing a deeper comprehension of macrophage heterogeneity

Impact of BDNF Val66Met Polymorphism on Myocardial Infarction: Exploring the Macrophage Phenotype

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin growth factor family, well known for its role in the homeostasis of the cardiovascular system. Recently, the human BDNF Val66Met single nucleotide polymorphism has been associated with the increased propensity for arterial thrombosis related to acute myocardial infarction (AMI). Using cardiac magnetic resonance imaging and immunohistochemistry analyses, we showed that homozygous mice carrying the human BDNF Val66Met polymorphism (BDNFMet/Met) undergoing left anterior descending (LAD) coronary artery ligation display an adverse cardiac remodeling compared to wild-type (BDNFVal/Val). Interestingly, we observed a persistent presence of pro-inflammatory M1-like macrophages and a reduced accumulation of reparative-like phenotype macrophages (M2-like) in the infarcted heart of mutant mice. Further qPCR analyses showed that BDNFMet/Met peritoneal macrophages are more pro-inflammatory and have a higher migratory ability compared to BDNFVal/Val ones. Finally, macrophages differentiated from circulating monocytes isolated from BDNFMet/Met patients with coronary heart disease displayed the same pro-inflammatory characteristics of the murine ones. In conclusion, the BDNF Val66Met polymorphism predisposes to adverse cardiac remodeling after myocardial infarction in a mouse model and affects macrophage phenotype in both humans and mice. These results provide a new cellular mechanism by which this human BDNF genetic variant could influence cardiovascular disease

Normal vascular function despite low levels of high-density lipoprotein cholesterol in carriers of the apolipoprotein A-I(Milano) mutant

BACKGROUND - Carriers of the apolipoprotein A-IMilano (apoA-IM) mutant have very low plasma high-density lipoprotein cholesterol (HDL-C) levels but do not show any history of premature cardiovascular disease or any evidence of preclinical vascular disease. HDL is believed to prevent the development of vascular dysfunction, which may well contribute to HDL-mediated atheroprotection. Whether the low HDL level of apoA-IM carriers is associated with impaired vascular function is presently unknown. METHODS AND RESULTS - The vascular response to reactive hyperemia, assessed by measuring postischemic increase in forearm arterial compliance, and the plasma concentration of soluble cell adhesion molecules were evaluated in 21 adult apoA-IM carriers, 21 age- and gender-matched nonaffected relatives (control subjects), and 21 healthy subjects with low HDL-C (low-HDL subjects). The average plasma HDL-C and apoA-I levels of apoA-IM carriers were remarkably lower than those of control subjects and significantly lower than those of low-HDL subjects. The postischemic increase in forearm arterial compliance in the apoA-IM carriers was 2-fold greater than in low-HDL subjects and remarkably similar to that of control subjects. Plasma soluble cell adhesion molecule levels were similar in apoA-IM carriers and control subjects but were greater in low-HDL subjects. When incubated with endothelial cells, HDL isolated from apoA-IM carriers was more effective than HDL from control and low-HDL subjects in stimulating endothelial nitric oxide synthase expression and activation and in downregulating tumor necrosis factor-\u3b1-induced expression of vascular cell adhesion molecule-1. CONCLUSIONS - Despite their very low HDL levels, apoA-IM carriers do not display typical features of impaired vascular function because of an improved activity of apoA-IM HDL in maintaining endothelial cell homeostasis

n-3 fatty acid ethyl ester administration to healthy subjects and to hypertriglyceridemic patients reduces tissue factor activity in adherent monocytes

n-3 Fatty acids are known to influence several functions of monocytes, including adhesion, cytokine synthesis, and superoxide generation. Monocytes express tissue factor, a membrane-bound glycoprotein, that acts as a catalyst in the coagulation cascade. In this study we evaluated the effects of administration of n-3 fatty acid ethyl esters to healthy volunteers and to hypertriglyceridemic patients on tissue factor activity (TF activity) in adherent monocytes. n-3 Fatty acids containing 75% eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (ratio of EPA to DHA, 1.34) were administered (3 g/d) to normal volunteers for 18 weeks. In addition, the effects of this treatment were evaluated in 30 hypertriglyceridemic patients for 24 weeks by using a double-blind, placebo-controlled study. TF activity in adherent monocytes was evaluated with a one-stage clotting assay. Plasma and monocyte fatty acid compositions were determined by gas-liquid chromatography. In healthy volunteers, n-3 fatty acids significantly reduced TF activity in adherent monocytes either in the unstimulated condition or after exposure to endotoxin. The inhibitory effect was observed after 12 weeks of treatment and was more pronounced after 18 weeks (> 70%, P < .001 versus baseline). Concomitantly, levels of EPA and DHA increased in plasma and monocyte lipids. Interestingly, after stopping treatment, monocyte TF activity remained inhibited for at least 14 weeks. Treatment with n-3 fatty acids for 24 weeks also resulted in a significant reduction of TF activity in adherent monocytes from hypertriglyceridemic patients (-31% and -40% in unstimulated and endotoxin-stimulated cells; P < .05 versus baseline).(ABSTRACT TRUNCATED AT 250 WORDS

Nitric oxide synthetic pathway in patients with microvascular angina and its relations with oxidative stress

A decreased nitric oxide (NO) bioavailability and an increased oxidative stress play a pivotal role in different cardiovascular pathologies. As red blood cells (RBCs) participate in NO formation in the bloodstream, the aim of this study was to outline the metabolic profile of L-arginine (Arg)/NO pathway and of oxidative stress status in RBCs and in plasma of patients with microvascular angina (MVA), investigating similarities and differences with respect to coronary artery disease (CAD) patients or healthy controls (Ctrl). Analytes involved in Arg/NO pathway and the ratio of oxidized and reduced forms of glutathione were measured by LC-MS/MS. The arginase and the NO synthase (NOS) expression were evaluated by immunofluorescence staining. RBCs from MVA patients show increased levels of NO synthesis inhibitors, parallel to that found in plasma, and a reduction of NO synthase expression. When summary scores were computed, both patient groups were associated with a positive oxidative score and a negative NO score, with the CAD group located in a more extreme position with respect to Ctrl. This finding points out to an impairment of the capacity of RBCs to produce NO in a pathological condition characterized mostly by alterations at the microvascular bed with no significant coronary stenosis

Nitric oxide synthetic pathway in red blood cells Is impaired in coronary artery disease

Background:All the enzymatic factors/cofactors involved in nitric oxide (NO) metabolism have been recently found in red blood cells. Increased oxidative stress impairs NO bioavailability and has been described in plasma of coronary artery disease (CAD) patients. The aim of the study was to highlight a potential dysfunction of the metabolic profile of NO in red blood cells and in plasma from CAD patients compared with healthy controls.Methods:We determined L-arginine/NO pathway by liquid-chromatography tandem mass spectrometry and high performance liquid chromatography methods. The ratio of oxidized and reduced forms of glutathione, as index of oxidative stress, was measured by liquid-chromatography tandem mass spectrometry method. NO synthase expression and activity were evaluated by immunofluorescence staining and ex-vivo experiments of L-[15N2]arginine conversion to L-[15N]citrulline respectively.Results:Increased amounts of asymmetric and symmetric dimethylarginines were found both in red blood cells and in plasma of CAD patients in respect to controls. Interestingly NO synthase expression and activity were reduced in CAD red blood cells. In contrast, oxidized/reduced glutathione ratio was increased in CAD and was associated to arginase activity.Conclusion:Our study analyzed for the first time the whole metabolic pathway of L-arginine/NO, both in red blood cells and in plasma, highlighting an impairment of NO pathway in erythrocytes from CAD patients, associated with decreased NO synthase expression/activity and increased oxidative stress