Iron stores are associated with asymptomatic atherosclerosis in healthy men of primary prevention.

BACKGROUND: The aim of our study was to assess the impact of increased iron stores on the presence of asymptomatic atherosclerosis in a cohort of healthy men. We anticipated that higher iron stores would be associated with higher soluble cluster of differentiation 163 (sCD163) concentrations, elevated markers of oxidative stress, inflammation and higher common carotid intima-media thickness, independently of traditional risk factors of atherosclerosis. METHODS: In this cross-sectional study that included 72 healthy men, we measured the ultrasonography of common carotid intima-media thickness (IACC), the ratio of plasma-circulating transferrin receptors concentration to plasma ferritin concentration, certain inflammatory and oxidative stress markers, insulin sensitivity, plasma lipids and markers of endothelial dysfunction. RESULTS: The plasma-circulating transferrin receptor concentration to plasma ferritin concentration ratio (TfR/F) showed significant association with IACC (r=-0·310, P=0·008 vs. r=0·295, P=0·012). Multivariate analysis confirmed that the correlation of TfR/F with IACC is independent of traditional risk factors of atherosclerosis. The TfR/F ratio correlated with other indicators of atherosclerotic process fibrinogen (r=-0·292, P=0·013), von Willebrand factor (vWf; r=0·284, P=0·017), sCD163 (r=0·239, P=0·043) and IL-8 (r=0·233, P=0·049). In multivariate analysis, TfR/F independently correlated with haemoglobin (ß=-0·220, P=0·047), fibrinogen (ß=-0·290, P=0·009), IL-8 (ß=0·227, P=0·039) and sCD163 (ß=0·244, P=0·025); however, when vWf was added, significant independent correlation was seen only with fibrinogen (ß=-0·301, P=0·007) and IL-8 (ß=0·219, P=0·047). In addition, we demonstrated the independent correlation of sCD163 with vWf (ß=0·240, P=0·040). CONCLUSIONS: Our study showed a clear association of body iron stores expressed by the TfR/F ratio with asymptomatic carotid atherosclerosis. TfR/F further exhibited an independent positive correlation with fibrinogen and a negative correlation with sCD163 and IL-8.

N-acetyl-D-glucosamine-coated polyamidoamine dendrimer promotes tumor-specific B cell responses via natural killer cell activation.

N-acetyl-D-glucosamine-coated polyamidoamine dendrimer (GN8P), exerting high binding affinity to rodent recombinant NKR-P1A and NKR-P1C activating proteins, was shown previously to delay the development of rat colorectal carcinoma as well as mouse B16F10 melanoma, and to potentiate antigen-specific antibody formation in healthy C57BL/6 mice via NK cell stimulation. In this study, we investigated whether GN8P also modulates tumor-specific B cell responses. Serum anti-B16F10 melanoma IgG levels, IgG2a mRNA expression, antibody dependent cell-mediated cytotoxicity (ADCC), and counts of plasma as well as antigen presenting B cells were evaluated in tumor-bearing C57BL/6 mice treated with GN8P and in respective controls. To reveal the mechanism of GN8P effects, the synthesis of interferon-gamma (IFN-γ) and interleukin-4 (IL-4), cytokines involved in regulation of immunoglobulin class switch, was determined. The GN8P treatment significantly elevated IgG, and particularly IgG2a, response against B16F10 melanoma, which led to augmented ADCC reaction. The significant increase in production of IFN-γ, which is known to support IgG2a secretion, was observed solely in NK1.1 expressing cell populations, predominantly in NK cells. Moreover, GN8P raised the number of plasma cells, and promoted antigen presenting capacity of I-A/I-E-positive B lymphocytes by up-regulation of their CD80 and CD86 co-stimulatory molecule expression. These results indicate that GN8P-induced enhancement of tumor-specific antibody formation is triggered by NK cell activation, and contributes to complexity of anticancer immune response involving lectin-saccharide interaction.

A comparison of the VASP index between patients with hemodynamically complicated and uncomplicated acute myocardial infarction.

INTRODUCTION: Critically-ill patients with ST-segment elevation myocardial infarction (STEMI) often present with insufficient gastroduodenal motility, liver hypoperfusion, and higher levels of circulating catecholamines. All of these factors can lead to reduced efficacy of clopidogrel, which is only available as a p.o. medication. The aim of the study was to compare clopidogrel effectiveness in unstable STEMI patients on mechanical ventilation with stable STEMI patients. MATERIALS AND METHODS: Two groups of twenty patients with STEMI were enrolled. One group (unstable) consisted of 20 hemodynamically unstable patients on mechanical ventilation and catecholamine support. The other group (stable) consisted of 20 control patients (all patients with STEMI in Killip I class). All patients were treated by primary Percutaneous coronary intervention. Blood samples were drawn before (baseline), at 4h (4h+), 24h (1d+) and 2 days (2d+) after clopidogrel administration. Clopidogrel efficacy was assessed by measurement of vasodilator-stimulated phosphoprotein phosphorylation index. RESULTS: The decrease in the vasodilator-stimulated phosphoprotein (VASP) index was substantially less in unstable patients compared with stable ones (ANOVA, P < 0.001). In stable patients, the VASP index decreased significantly by 20% at 4h+ and by 34% at 1d+, and remained significantly decreased by 31% at 2d+. In unstable patients, the VASP decreased nonsignificantly by 8% at 4h+, and no further decrease of VASP was present (-7% at 1d+, -11% at 2d+). CONCLUSIONS: Laboratory clopidogrel efficacy is lower in patients with MI and severe hemodynamic instability, probably due to splanchnic and liver hypoperfusion and catecholamine use.

N-Acetyl-D-glucosamine-coated polyamidoamine dendrimer modulates antibody formation via natural killer cell activation.

N-Acetyl-D-glucosamine-coated polyamidoamine dendrimer (GlcNAc8) was shown previously to exhibit binding affinity to the rat recombinant NKR-P1 molecule (known in mice also as NK1.1) and to induce NK cell-mediated cytotoxicity. In this study, we investigated whether GlcNAc8 modulates antibody formation as activated NK cells were reported to participate in its regulation. C57BL/6 mice treated with GlcNAc8 and intact controls were immunized either with sheep red blood cells (SRBCs), 2,4-dinitrophenylated-lipopolysaccharide (DNP-LPS) or keyhole limpet hemocyanin (KLH) for evaluation of splenic antibody forming cell counts and serum immunoglobulin (Ig) levels. In vitro Ig formation was determined using supernatants of spleen mononuclear cells (SMCs) and CD49b or NK1.1-depleted SMC subpopulations. Serum antigen-specific IgG2a levels were also measured in DBA/2 and BALB/c mice (NK1.1-negative mouse strains on the basis of flow cytometric analysis) which possess different Nkr-p1c gene form than C57BL/6 ones. A significant increase in anti-SRBC IgG forming cells, serum levels of anti-KLH as well as anti-DNP IgG and IgG2a was observed after GlcNAc8 administration in C57BL/6 mice. IgM levels in supernatants of SMCs stimulated in vitro simultaneously with DNP-LPS and GlcNAc8 were significantly mounted compared with supernatants of SMCs primed with the antigen alone, but this enhancement was blocked after depletion of CD49b-positive or NK1.1-positive cells. In DBA/2 and BALB/c mice, GlcNAc8 influenced neither serum levels of anti-KLH nor anti-DNP IgG2a. These results indicate that GlcNAc8-induced upregulation of antibody formation is triggered by NK cell stimulation and depends on expressed NKR-P1 isoforms, particularly NKR-P1C.

N-acetyl-D-glucosamine substituted calix[4]arenes as stimulators of NK cell-mediated antitumor immune response.

A series of calixarenes substituted with 2-acetamido-2-deoxy-beta-D-glucopyranose linked by a thiourea spacer was prepared and tested for binding activity to heterogeneously expressed activation receptors of the rat natural killer cells NKR-P1, and the receptor CD69 (human NK cells, macrophages). In the case of NKR-P1, the binding affinity of beta-D-GlcNAc-substituted calixarenes carrying two or four sugar units was in a good agreement with the inhibitory potencies of the linear chitooligomers (chitobiose to chitotetraose) reported previously. The influence of GlcNAc substitution of the calixarene skeleton on binding affinity for CD69 receptor was more profound and the 5,11,17,23-tetrakis[N-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-thioureido]-25,26,27,28-tetrapropoxycalix[4]arene (cone) (1) proved to be the best CD69 ligand identified to date. Lower GlcNAc substitution led to dramatic decrease of the binding activity (by about 1.5 order of magnitude per one GlcNAc unit). The immunostimulating activity results with the newly synthesized GlcNAc tetramers on calixarene scaffolds exhibited stimulation of natural cytotoxicity of human PBMC in concentrations 10(-4) and 10(-8)M. These calix-sugar compounds were superior to the previously tested PAMAM-GlcNAc(8)5.