High Avidity Anti-β2-Glycoprotein i Antibodies Activate Human Coronary Artery Endothelial Cells and Trigger Peripheral Blood Mononuclear Cell Migration

Anti-β2-glycoprotein I antibodies (aβ2GPI) represent a potential pathogenic candidate for coronary artery diseases. High avidity aβ2GPI (HAv aβ2GPI) are known to be associated with thrombotic and obstetric manifestations in patients with antiphospholipid syndrome, who are also susceptible to the development of premature atherosclerosis. However, there is little information about how human coronary artery endothelial cells (HCAEC) are affected by HAv aβ2GPI. The purpose of our study was to evaluate the pathophysiological effects of HAv aβ2GPI on HCAEC and determine their influence on cytokine expression and migration of peripheral blood mononuclear cells. Following the two hit hypothesis, we co-stimulated HAv aβ2GPI-treated HCAEC in the presence and absence of the acute phase protein serum amyloid A (SAA). HAv aβ2GPI induced in vitro HCAEC dysfunction, through the ERK1/2 signaling pathway, promoted the expression of chemokines (MCP-1, GROα and IL-8) and IL-6, which led to the attraction and migration of peripheral blood mononuclear cells. These effects were potentiated and intensified in conditions with SAA, indicating that HAv aβ2GPI, in the presence of physiological concentrations of acute-phase proteins represent pathogenic autoantibodies, which could lead to the development of premature atherosclerosis and/or thrombosis development

Atorvastatin in stable angina patients lowers CCL2 and ICAM1 expression: Pleiotropic evidence from plasma mRNA analyses.

Objective: Statin pleiotropy is still an evolving concept, and the lack of clarity on this subject is due at least in part to the lack of a definitive biomarker for statin pleiotropy. Using plasma mRNA analysis as a novel research tool for the non-invasive in vivo assessment of gene expression in vascular beds, we hypothesised that atorvastatin lowers the plasmamRNA level from statin pleiotropy-target genes, and the reduction is independent of the reduction of low-density lipoprotein cholesterol (LDL-C). Design and methods: Forty-four patients with stable angina received atorvastatin therapy (20 mg/day, 10 weeks). Plasma chemokine (C-C motif) ligand 2 (CCL2) and intercellular adhesion molecule-1 (ICAM1) mRNA levels and their protein concentrations (MCP-1, sICAM-1) were analysed before and after the treatment. Plasma vascular adhesion molecule-1 (sVCAM-1) concentrations were also analysed. Results: Atorvastatin lowered plasma mRNA levels (CCL2: −31.76%, p = 0.037; ICAM1: −34.09%, p b 0.001) and MCP-1 protein concentration (−18.88%, p = 0.008) but did not lower sICAM-1 and sVCAM-1 protein concentrations, and the decreases appeared to be independent from the lowering of LDL-C. The plasma mRNA levels correlated with their protein concentrations following statin treatment only. Conclusion: Our results significantly strengthen the clinical evidence in support of statin pleiotropy. Furthermore, this unique simultaneous measurement of plasma mRNAs and their protein concentrations offers an advanced non-invasive in vivo assessment of the circulation patholog

Binding of plasma proteins to titanium dioxide nanotubes with different diameters

Mukta Kulkarni,1,* Ajda Flašker,1,* Maruša Lokar,1 Katjuša Mrak-Poljšak,2 Anca Mazare,3 Andrej Artenjak,4 Saša Čučnik,2 Slavko Kralj,5 Aljaž Velikonja,1 Patrik Schmuki,3 Veronika Kralj-Iglič,6 Snezna Sodin-Semrl,2,7 Aleš Iglič11Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia; 2Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia; 3Department of Materials Science and Engineering, University of Erlangen Nuremberg, Erlangen, Germany; 4Sandoz Biopharmaceuticals Mengeš, Lek Pharmaceuticals dd, Menges, Slovenia; 5Department for Materials Synthesis, Institute Jožef Stefan (IJS), Ljubljana, Slovenia; 6Faculty of Health Studies, University of Ljubljana, Ljubljana, Slovenia; 7Faculty of Mathematics, Natural Science and Information Technology, University of Primorska, Koper, Slovenia *These authors contributed equally to this workAbstract: Titanium and titanium alloys are considered to be one of the most applicable materials in medical devices because of their suitable properties, most importantly high corrosion resistance and the specific combination of strength with biocompatibility. In order to improve the biocompatibility of titanium surfaces, the current report initially focuses on specifying the topography of titanium dioxide (TiO2) nanotubes (NTs) by electrochemical anodization. The zeta potential (ζ-potential) of NTs showed a negative value and confirmed the agreement between the measured and theoretically predicted dependence of ζ-potential on salt concentration, whereby the absolute value of ζ-potential diminished with increasing salt concentrations. We investigated binding of various plasma proteins with different sizes and charges using the bicinchoninic acid assay and immunofluorescence microscopy. Results showed effective and comparatively higher protein binding to NTs with 100 nm diameters (compared to 50 or 15 nm). We also showed a dose-dependent effect of serum amyloid A protein binding to NTs. These results and theoretical calculations of total available surface area for binding of proteins indicate that the largest surface area (also considering the NT lengths) is available for 100 nm NTs, with decreasing surface area for 50 and 15 nm NTs. These current investigations will have an impact on increasing the binding ability of biomedical devices in the body leading to increased durability of biomedical devices. Keywords: protein binding, serum amyloid A, β2-glycoprotein I, immunoglobulin G, histone II

Avidity of anti-β2-glycoprotein i antibodies in patients with antiphospholipid syndrome

Antibodies against β2-glycoprotein I (anti-β2GPI) are one of the hallmarks of the antiphospholipid syndrome (APS). However, they are heterogenic regarding their epitope specificity, pathogenic mechanisms and their avidity. In the current study we present some outstanding issues about avidity of anti-β2GPI antibodies. Our results confirmed that high avidity anti-β2GPI are associated with thrombosis and APS, while in low avidity anti-β2GPI group non-APS (predominantly systemic lupus erythematosus) patients prevailed. © The Author(s), 2012. Reprints and permissions: http://www.sagepub.co.uk/journalsPermissions.nav

Immunoreactivity and avidity of IgG anti-beta 2-glycoprotein I antibodies from patients with autoimmune diseases to different peptide clusters of beta 2-glycoprotein I

The pathogenicity of antibodies against β2-glycoprotein I (anti-β2GPI) depends on multiple factors such as subclass type, epitope binding and avidity. Due to their large heterogeneity, their impact on antiphospholipid syndrome (APS) onset is still not fully clarified. We studied the binding characteristics of IgG anti-β2GPI with known avidity from sera of 201 autoimmune patients (87 with APS, 67 with APS associated with systemic lupus erythematosus (SLE), 47 with only SLE) to six β2GPI peptides corresponding to amino acid clusters on domains I-II, II, III and III-IV by indirect ELISA and evaluated their association with clinical features of APS. Peptides A (LKTPRV; domain I-II), B (KDKATF; domain IV) and C (TLRVYK; domain III) were derived from a hexapeptide phage display library previously shown to react with pathogenic monoclonal anti-β2GPI. Peptides D (NGPANSK; domain III), E (YNPLWFV; domain II) and F (KMDGNHP; domain III-IV) represent surface amino acid clusters on β2GPI. The percentage of patients positive for peptides were observed as follows: 30.3 % for peptide D, 28.90 % for B, 25.9 % for C, 24.9 % for E, 24.4 % for F and 10.0 % for A. The anti-peptide antibodies in studied serum samples were predominantly of heterogeneous avidity, followed by law avidity anti-peptide antibodies, whereas only a few were of high avidity. Positive and negative correlations were found between several anti-peptide antibodies and the rate of thrombosis. Our results indicated diverse reactivity of IgG anti-β2GPI to different epitopes on β2GPI. Classification of IgG anti-β2GPI into subgroups regarding epitope specificity and avidity could represent an additional tool in understanding their pathogenicity in APS