Oral administration of Domain-I of beta-2glycoprotein-I induces immunological tolerance in experimental murine antiphospholipid syndrome.

It is well established that the humoral immunity in antiphospholipid syndrome (APS) is presented by circulating pathogenic anti-ß2GPI autoantibodies targeting mainly domain I of the ß2GPI protein, playing a major role in the disease pathogenesis. Previously, we have demonstrated that treatment of experimental APS mice with tolerogenic dendritic cells loaded with domain-I was more efficient in tolerance induction than with the whole molecule or domain-V. In the current study we had orally administered a domain-I derivative of the ß2GPI molecule, as a new therapeutic approach to induce oral tolerance in this mouse model of APS. BALB/c mice immunized with ß2GPI, were fed with either domain-I, domain-V derivative or the complete ß2GPI protein. ß2GPI immunized mice developed experimental APS which were fed with domain-I significantly had decreased fetal loss (p < 0.004), a lower size of thrombi (p < 0.001) and lower circulating anti-ß2GPI Abs in comparison to mice fed with domain-V or PBS (p < 0.002). Likewise, Domain-I fed mice had a lowered inflammatory response, exhibited by decreased expression of inflammatory cytokines (IFNγ, IL-6, IL-17) and elevated production of IL-10 anti-inflammatory cytokine by splenocytes. Moreover, the anti-inflammatory response in the domain-I fed APS mice was associated with increased circulating miRNA variations (155, 146, 182, 98) by RT-PCR, which are associated with immunomodulation of the immune network. We propose that oral tolerance with domain-I can be a novel therapy for patients with APS.

Hydroxychloroquine partially prevents endothelial dysfunction induced by anti-beta-2-GPI antibodies in an in vivo mouse model of antiphospholipid syndrome.

BACKGROUND: Antiphospholipid syndrome is associated with endothelial dysfunction, which leads to thrombosis and early atheroma. Given that hydroxychloroquine has anti-thrombotic properties in lupus, we hypothesized that it could reduce endothelial dysfunction in an animal model of antiphospholipid syndrome. We evaluated the effect of hydroxychloroquine in preventing endothelial dysfunction in a mouse model of antiphospholipid syndrome. METHODS: Antiphospholipid syndrome was induced by an injection of monoclonal anti-beta-2-GPI antibodies. Vascular reactivity was evaluated in mesenteric resistance arteries isolated from mice 3 weeks (APL3W) after receiving a single injection of anti-beta-2-GPI antibodies and after 3 weeks of daily oral hydroxychloroquine treatment (HCQ3W) compared to control mice (CT3W). We evaluated endothelial dysfunction by measuring acetylcholine-mediated vasodilation. A pharmacological approach was used to evaluate NO synthase uncoupling (tetrahydrobiopterin) and the generation of reactive oxygen species (Tempol). RESULTS: Impaired acetylcholine-mediated dilation was evidenced in mice 3 weeks after anti-beta-2-GPI antibodies injection compared to CT3W, by reduced maximal dilation (p<0.0001) and sensitivity (pKd) (p = 0.01) to acetylcholine. Hydroxychloroquine improved acetylcholine-dependent dilation, on pKd (p = 0.02) but not maximal capacity compared to untreated mice. The addition of tetrahydrobiopterin (p = 0.02) and/or Tempol (p = 0.0008) improved acetylcholine-mediated dilation in APL3W but not in HCQ3W. CONCLUSIONS: We demonstrated that endothelial dysfunction in mouse resistance arteries persisted at 3 weeks after a single injection of monoclonal anti-beta-2-GPI antibodies, and that hydroxychloroquine improved endothelium-dependent dilation at 3 weeks, through improvement of NO synthase coupling and oxidative stress reduction.

A rapid, highly sensitive and culture-free detection of pathogens from blood by positive enrichment.

Molecular diagnostics is a promising alternative to culture based methods for the detection of bloodstream infections, notably due to its overall lower turnaround time when starting directly from patient samples. Whole blood is usually the starting diagnostic sample in suspected bloodstream infections. The detection of low concentrations of pathogens in blood using a molecular assay necessitates a fairly high starting volume of blood sample in the range of 5-10mL. This large volume of blood sample has a substantial accompanying human genomic content that interferes with pathogen detection. In this study, we have established a workflow using magnetic beads coated with Apolipoprotein H that makes it possible to concentrate pathogens from a 5.0mL whole blood sample, thereby enriching pathogens from whole blood background and also reducing the sample volume to ~200µL or less. We have also demonstrated that this method of enrichment allows detection of 1CFU/mL of Escherichia coli, Enterococcus gallinarum and Candida tropicalis from 5mL blood using quantitative PCR; a detection limit that is not possible in unenriched samples. The enrichment method demonstrated here took 30min to complete and can be easily integrated with various downstream molecular and microbiological techniques.

Long-chain fatty acid oxidation changes in a ß2 glycoprotein I-induced preeclampsia-like mouse model.

INTRODUCTION: Abnormal fatty acid oxidation (FAO) and lipid metabolism have been found related to preeclampsia (PE). Antiphospholipid syndrome (APS) as a clinical risk factor for PE has also been reported with abnormal lipid metabolism. However, the role of FAO in PE accompanied with APS is unknown. We aimed to investigate long-chain FAO changes in a PE-like rodent model induced by beta 2-glycoprotein I (ß2GPI). METHODS: The PE-like model was established by injection of ß2GPI (ß2GPI group) or normal saline (control group) into C57BL/6J mice which were sacrificed on day 14 or 18 of gestation. Serum levels of anti-cardiolipin antibodies (aCL), anti-ß2GPI antibodies (aß2GPI) and serum lipids were assayed. Lipid deposition in the placenta and maternal liver was detected by lipid staining. Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) mRNA and protein expression in the placenta and maternal liver was analyzed. RESULTS: The ß2GPI group showed PE-like symptoms including hypertension, proteinuria and adverse pregnancy outcomes. Serum aCL, aß2GPI, free fatty acid (FFA) and triglyceride (TG) levels in the ß2GPI group were significantly elevated compared with the corresponding control group (P < 0.05), while cholesterol showed no significant changes. Placenta and maternal liver fatty infiltration was found in the ß2GPI group. LCHAD mRNA and protein expression in the placenta and maternal liver in the ß2GPI group were significantly elevated compared with the corresponding control group (P < 0.05). CONCLUSION: ß2GPI can induce PE-like symptoms, elevated serum FFA and TG, and abnormal LCHAD expression in pregnant mice. Changes in long-chain FAO could be a factor linking PE and APS.

In vivo modulation of angiogenesis by beta 2 glycoprotein I.

Beta 2 glycoprotein I (ß2GPI) is the major auto antigen in the antiphospholipid syndrome but also interacts with fibrinolytic and angiogenic proteins. The aim of this study was to examine the angiogenic potential of ß2GPI in vivo in ß2GPI deficient mice utilizing angiogenic assays. ß2GPI deficient mice show increased microvessel formation in comparison to ß2GPI replete controls when injected with growth factor free-matrigel implants. However, microvessel formation in matrigel plugs of ß2GPI deficient mice was less than in ß2GPI replete mice when basic fibroblast growth factor (bFGF) was included in the matrigel. Hemoglobin content was higher in vascular endothelial growth factor (VEGF) containing-matrigel plugs in the ß2GPI deficient mouse demonstrating that the lack of ß2GPI led to increased extravasation by VEGF. Melanoma B16F10 tumour growth was enhanced in ß2GPI deficient mice. Melanoma microvessel density was increased in ß2GPI deficient mice but the proliferation rate of tumour cells (determined by Ki67 immunohistochemistry) was unaffected by the presence or absence of ß2GPI. Subcutaneous delivery of native human ß2GPI by the ALZET osmotic pump did not affect melanoma tumour growth in ß2GPI deficient mice. We conclude that the in vivo unopposed action of ß2GPI is anti-angiogenic however this function is modified in the presence of a strong angiogenic stimulus into stabilization of vessel formation. Although the presence of ß2GPI attenuates vessel sprouting in certain tumours, no survival benefit is conferred to tumour bearing animals. This does not preclude the potential benefit of modified or fragments of ß2GPI in anti-angiogenesis research.

Immunization of LDL receptor-deficient mice with beta2-glycoprotein 1 or human serum albumin induces a more inflammatory phenotype in atherosclerotic plaques.

Antiphospholipid antibodies are a risk factor for venous and arterial thrombosis and may contribute to the development of atherosclerosis.The aim of this study was to investigate whether antibodies to human beta2-glycoprotein 1 (beta2GP1), as a model of antiphospholipid antibodies, modify the phenotype of atherosclerotic lesions. LDL receptor-deficient mice were immunized with human beta2GP1, human serum albumin (HSA), or not immunized, and fed a high-cholesterol diet for 14 weeks. Some mice also received pravastatin. Immunization with human beta2GP1 or HSA resulted in formation of autoantibodies recognizing murine beta2GP1 or murine albumin, respectively. We quantified atherosclerotic lesion development and mRNA levels of inflammation associated proteins in the thoraco-abdominal aorta as well as lesion development,cellular composition and collagen content in the aortic roots. Immunization with beta2GP1 or HSA had no effect on lesion size,but modified the expression in plaque areas of several inflammation-associated proteins. Expression of matrix metalloproteinase-9, tissue factor, interferon-gamma and CD25 was highest in the thoraco-abdominal aorta of beta2GP1-immunized mice, lowest in non-immunized mice and intermediate in HSA-immunized animals. Immunization with beta2GP1, but not HSA, resulted in a lower smooth muscle cell and collagen content of lesions in aortic roots. Statin treatment partially reversed the effects of beta2GP1 immunization. We conclude that immunization with beta2GP1, and to a lesser extent with HSA, leads to modifications in the cellular and protein composition of atherosclerotic plaques, which are associated with a more inflammatory phenotype. Statin treatment partially prevents these changes.