Oxidised LDL and Anti-Oxidised LDL Antibodies Are Reduced by Lipoprotein Apheresis in a Randomised Controlled Trial on Patients with Refractory Angina and Elevated Lipoprotein(a)

Aims: An abundance of epidemiological evidence demonstrates that elevated lipoprotein(a) (Lp(a)) represents a significant contributing risk factor towards the development of cardiovascular disease. In particular, raised Lp(a) may play a mechanistic role in patients with refractory angina. Studies have also shown a correlation between oxidised LDL (oxLDL) levels and atherosclerotic burden as well as rates of cardiovascular events. Antibodies against oxLDL (anti-oxLDL) are involved in the removal of oxLDL. Lipoprotein apheresis (LA), which removes lipoproteins using extra-corporeal processes, is an established means of reducing Lp(a), and thereby reduces cardiovascular events. The aim of this study was to investigate the effect of LA on oxLDL and anti-oxLDL levels amongst those with refractory angina in the context of raised Lp(a). Methods: We performed a sub-study within a randomised controlled crossover trial involving 20 patients with refractory angina and raised Lp(a) > 500 mg/L, comparing the effect of three months of blinded weekly LA or sham, followed by crossover to the opposite study arm. We utilized enzyme-linked immunosorbent assays (ELISA) to quantify oxLDL and IgG/ IgM anti-oxLDL antibody levels at baseline and following three months of active LA or sham sessions. Results: Following three months of LA, there was a 30% reduction in oxLDL from 0.37 ± 0.06 to 0.26 ± 0.04 with a mean drop of -0.11 units (U) (95% CI -0.13, -0.09) compared to no significant change with sham therapy (p < 0.0001 between treatment arms). LA also led to a 22% reduction in levels of IgG and IgM anti-oxLDL, again with no significant change demonstrated during sham (p = 0.0036 and p = 0.012, respectively, between treatment arms). Conclusion: Amongst patients with refractory angina in the context of elevated Lp(a), LA significantly lowers levels of oxLDL and anti-oxLDL antibodies, representing potential mechanisms by which LA yields symptomatic and prognostic benefits in this patient cohort.

Anti-Oxidized LDL Antibodies and Coronary Artery Disease: A Systematic Review

Antibodies to oxidized LDL (oxLDL) may be associated with improved outcomes in cardiovascular disease. However, analysis is restricted by heterogenous study design and endpoints. Our objective was to conduct a comprehensive systematic review assessing anti-oxLDL antibodies in relation to coronary artery disease (CAD). Through a systematic literature search, we identified all studies assessing the relationship of either, IgG or IgM ox-LDL/ copper-oxLDL/ malondialdehyde-LDL, with coronary atherosclerosis or cardiovascular events in populations with, and without, established CAD. Systematic review best practices were adhered to and study quality was assessed. An initial electronic database search identified 2059 records, which was subsequently followed by abstract and full-text review. Finally, we included 18 studies with over 1811 patients with CAD. The studies varied according to populations studied, conventional cardiovascular risk factors and interventional modalities used to assess CAD. IgM anti-oxLDL antibodies were found to indicate protection from more severe CAD and possibly cardiovascular events, whilst the relationship with IgG is more complex and difficult to elucidate, with studies reporting divergent results. In this systematic review, there is evidence that suggests a relationship between anti-oxLDL antibodies and CAD, especially for the IgM subclass. However, further studies, with well-characterized prospective cohorts, will be important to clarify these associations.

Oxidized LDL and anti-oxidized LDL antibodies in atherosclerosis - Novel insights and future directions in diagnosis and therapy<sup/>

We provide an up-to-date overview of current topics surrounding oxidized low-density lipoprotein (oxLDL) and its related antibodies in the quest to better identify the individuals at risk of cardiovascular disease and atherosclerotic plaques with unfavorable characteristics. We discuss the potential of oxLDL and anti-oxLDL antibodies as serum biomarkers of cardiovascular disease and emerging studies examining the targeting of arterial oxLDL for imaging and therapeutic delivery.

A review of the peri-operative risk stratification assessment tools used for the prediction of cardiovascular complications in non-cardiac surgery

The development of atherosclerosis is a complex process that involves several inflammatory mechanisms. The evolution of a fatty streak to a mature occlusive atheromatous plaque occurs over several decades. However, during acute plaque rupture, to a varying degree, these same inflammatory systems are involved.Evidence exists that suggests a relationship between the activated inflammatory pathways; in the setting of lower respiratory tract or urinary tract infections and cardiac events such as unstable angina or myocardial infarctions.Peripheral vascular disease patients demonstrate atheromatous disease throughout their arterial tree, with coronary artery involvement in a significant proportion of individuals. The stress that a surgical intervention creates may be the catalyst for an acute coronary syndrome through the activation of these inflammatory pathways. Individual responses to the surgical insult are unpredictable and the extent to which the inflammatory mechanisms are stimulated is variable. The measurements of inflammatory biomarkers, such as C-reactive protein, have been associated with adverse short- and long-term mortality in patients who experience an acute coronary syndrome.This review article looks at the previous assessment tools that have been developed over time to try and predict the peri-operative risk of patients undergoing non-cardiac surgery, based on traditional patient parameters. We also explore the use of bio-markers in addition to these characteristics and how future work is being developed to look at the potential use of these to improve individual risk profiles.

In vivo mapping of vascular inflammation using the translocator protein tracer 18F-FEDAA1106

Noninvasive imaging methods are required to monitor the inflammatory content of atherosclerotic plaques. FEDAA1106 (N-(5-fluoro-2-phenoxyphenyl)-N-(2-(2-fluoroethoxy)-5-methoxybenzyl) acetamide) is a selective ligand for TSPO-18kDa (also known as peripheral benzodiazepine receptor), which is expressed by activated macrophages. We compared 18F-FEDAA1106 and 2-deoxy-2-[18F]fluoro-d-glucose (18F-FDG, a marker of glucose metabolism) for positron emission tomographic (PET) imaging of vascular inflammation. This was tested using a murine model in which focal inflammation was induced in the carotid artery via placement of a constrictive cuff. Immunostaining revealed CD68-positive cells (macrophages) at a disturbed flow site located downstream from the cuff. Dynamic PET imaging using 18F-FEDAA1106 or 18F-FDG was registered to anatomic data generated by computed tomographic (CT)/CT angiography. Standardized uptake values were significantly increased at cuffed compared to contralateral arteries using either 18F-FEDAA1106 (p < .01) or FDG (p < .05). However, the 18F-FEDAA1106 signal was significantly higher at the inflamed disturbed flow region compared to the noninflamed uniform flow regions, whereas differences in FDG uptake were less distinct. We conclude that 18F-FEDAA1106 can be used in vivo for detection of vascular inflammation. Moreover, the signal pattern of 18F-FEDAA1106 corresponded with vascular inflammation more specifically than FDG uptake.

Heterogeneity in neutrophil microparticles reveals distinct proteome and functional properties

Altered plasma neutrophil microparticle levels have recently been implicated in a number of vascular and inflammatory diseases, yet our understanding of their actions is very limited. Herein, we investigate the proteome of neutrophil microparticles in order to shed light on their biological actions. Stimulation of human neutrophils, either in suspension or adherent to an endothelial monolayer, led to the production of microparticles containing >400 distinct proteins with only 223 being shared by the two subsets. For instance, postadherent microparticles were enriched in alpha-2 macroglobulin and ceruloplasmin, whereas microparticles produced by neutrophils in suspension were abundant in heat shock 70 kDa protein 1. Annexin A1 and lactotransferrin were expressed in both microparticle subsets. We next determined relative abundance of these proteins in three types of human microparticle samples: healthy volunteer plasma, plasma of septic patients and skin blister exudates finding that these proteins were differentially expressed on neutrophil microparticles from these samples reflecting in part the expression profiles we found in vitro. Functional assessment of the neutrophil microparticles subsets demonstrated that in response to direct stimulation neutrophil microparticles produced reactive oxygen species and leukotriene B₄ as well as locomoted toward a chemotactic gradient. Finally, we investigated the actions of the two neutrophil microparticles subsets described herein on target cell responses. Microarray analysis with human primary endothelial cells incubated with either microparticle subset revealed a discrete modulation of endothelial cell gene expression profile. These findings demonstrate that neutrophil microparticles are heterogenous and can deliver packaged information propagating the activation status of the parent cell, potentially exerting novel and fundamental roles both under homeostatic and disease conditions.

Experimental autoimmune vasculitis: an animal model of anti-neutrophil cytoplasmic autoantibody-associated systemic vasculitis

The morbidity burden associated with anti-neutrophil cytoplasmic autoantibody-associated vasculitis is increasing, and many novel biological therapies are now entering the drug development pipeline. There is thus an urgent need to develop a representative animal model to facilitate testing of these agents. We previously examined the effect of antineutrophil cytoplasmic autoantibody on leukocyte-endothelial interactions in WKY rats via immunization with human myeloperoxidase. We now seek to extend this model so that all animals reliably develop crescentic glomerulonephritis and lung hemorrhage. We also wish to investigate whether there is a genetic contribution to vasculitis development in this rat strain. Using escalating doses of human myeloperoxidase, we found that a dose of 1600 microg/kg induced pauci-immune crescentic glomerulonephritis and lung hemorrhage in all immunized animals. We also found that the addition of pertussis toxin and killed Mycobacterium tuberculosis to the adjuvant when immunizing with 400 microg/kg of myeloperoxidase resulted in crescentic glomerulonephritis and lung hemorrhage in all animals. However, when Lewis, Wistar Furth, or Brown Norway rats were immunized using a similar protocol, no animals developed hematuria or glomerulonephritis, despite having identical levels of anti-human myeloperoxidase antibodies. We conclude that, by adjusting the immunization regimen, all WKY rats immunized with myeloperoxidase develop experimental autoimmune vasculitis, thus facilitating future therapeutic studies. The resistance of Lewis rats to experimental autoimmune vasculitis provides a genetic basis for future studies of anti-myeloperoxidase antibody-associated vasculitis.

The class II phosphoinositide 3-kinase PI3K-C2beta regulates cell migration by a PtdIns3P dependent mechanism

The biological and pathophysiological significance of class II phosphoinositide 3-kinase enzyme expression currently remains unclear. Using an in vitro scrape wound assay and time-lapse video microscopy, we demonstrate that cell motility is increased in cultures expressing recombinant PI3K-C2beta enzyme. In addition, overexpression of PI3K-C2beta transiently decreased cell adhesion, stimulated the formation of cytoplasmic processes, and decreased the rate of cell proliferation. Consistent with these observations, expression of PI3K-C2beta also decreased expression of alpha4 beta1 integrin subunits. Using asynchronous cultures, we show that endogenous PI3K-C2beta is present in lamellipodia of motile cells. When cells expressing recombinant PI3K-C2beta were plated onto fibronectin, cortical actin staining increased markedly and actin rich lamellipodia and filopodia became evident. Overexpression of a 2xFYVE(Hrs) domain fusion protein abolished this response demonstrating that the effect of PI3K-C2beta on the reorganization of actin filaments is dependent upon PtdIns3P. Finally, overexpression of PI3K-C2beta increased GTP loading of Cdc42. Our data demonstrates for the first time, that PI3K-C2beta plays a regulatory role in cell motility and that the mechanism by which it reorganizes the actin cytoskeleton is dependent upon PtdIns3P production.

Development of the BD-QoL: a quality of life measure specific to Behçet's disease

OBJECTIVE

Current outcome measures for patients with Behçet's disease (BD) are impairment-focused and do not necessarily take account of the wider impact of the condition on the individual's lifestyle. Our aim was to develop a disease-specific measure of quality of life (QoL) for BD.

METHODS

The content of the BD-QoL was derived from qualitative interviews with patients using a "needs-based" approach to identify items. A postal survey was used to test the scaling properties, reliability, internal consistency, and validity of the new questionnaire using Rasch analysis. A second postal survey was used to assess test-retest reliability and internal consistency and to provide further evidence of the validity of the questionnaire.

RESULTS

Main themes emerging from the qualitative interviews included relationships, emotions, limitations in day to day activities, and self-image. From these themes 71 statements were chosen as potential items for the BD-QoL. After analysis, 30 items of the BD-QoL emerged free of item bias for age and sex. Fit to the Rasch model was excellent. In the second postal survey test-retest reliability of the 30 item BD-QoL was 0.84.

CONCLUSION

The BD-QoL provides the clinician with a simple, reliable, and valid tool for assessing the influence of interventions for BD and for evaluating models of service delivery. It is well accepted by patients, and has excellent scaling and psychometric properties. The BD-QoL complements information obtained through BD-specific disease activity scales.