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Newcastle, Australia

Phang M.,University of Newcastle | Lincz L.F.,Hunter Haematology Research Group | Garg M.L.,University of Newcastle
Journal of Nutrition | Year: 2013

Although long-chain n3 polyunsaturated fatty acids [n3 PUFAs; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] have been reported to reduce platelet aggregation, the available evidence on this is equivocal. We previously demonstrated that the acute effects of n3 PUFA supplementation on platelet aggregation are sex specific. We aimed to determine if this gender bias is maintained during long-term n3 PUFA supplementation and whether this translates to other hemostatic markers. A double-blinded, randomized, placebo controlled trial was conducted in 94 healthy men and women. Platelet aggregation, thromboxane (TX) B2, P-selectin (P-sel), von Willebrand factor (vWF), and plasminogen activator inhibitor-1were measured at baseline and 4 wk postsupplementationwith EPA-rich (1000 mgEPA:200mg DHA) or DHA-rich (200 mg EPA:1000 mg DHA) oil capsules daily. The effects of n3 PUFA on platelet activitywere compared betweenmen and women. In men and women combined, EPA and DHA reduced platelet aggregation following 4 wk of supplementation relative to placebo (211.8%, P = 0.016; and 214.8%, P = 0.001, respectively). In subgroup analyses, in men, only the EPA treatment reduced platelet aggregation by 218.4%compared with placebo (P = 0.005) andwomen (P = 0.011). In contrast, in women, only the DHA treatment reduced platelet aggregation (218.9%) compared with placebo (P = 0.001) andmen (P = 0.017). Significant sex × treatment interactions were also observed on hemostatic markers and uptake of n3 PUFAs. The significant interactions between sex and specific, supplemental, long-chain n3 PUFAs result in platelet aggregation being differentially affected in men and women. With respect to thrombotic disease risk, men are more likely to benefit from supplementation with EPA, whereas women are more responsive to DHA. J. Nutr. 143: 457-463, 2013.©2013 American Society for Nutrition.

Clancy P.,James Cook University | Lincz L.F.,Hunter Haematology Research Group | Maguire J.,University of Newcastle | McEvoy M.,University of Newcastle | And 2 more authors.
BioFactors | Year: 2014

Tenascin-C (Tn-C) is an endogenous ligand of toll-like receptor-4 (TLR-4); a key signalling molecule associated with chronic inflammatory conditions. Both Tn-C and TLR-4 are increased in unstable human atheroma, but their effects on local inflammatory conditions have not been investigated. The aim of the present study was to investigate the association and functional implications of Tn-C/TLR-4 signalling in large artery atherosclerotic stroke. Plasma Tn-C was measured by ELISA and found to be higher in recent stroke patients (n=336; median 12.77 μg/mL, inter-quartile range 10.23-15.74 μg/mL) than in controls (n=321; median 11.31 μg/mL, inter-quartile range 8.89-13.90 μg/mL), P<0.001. Plasma Tn-C was also independently positively associated with stroke (odds ratio for highest Tn-C quartile 2.27, 95% confidence interval 1.37-3.76). Assessment of Tn-C associated chronic cytokine secretion was performed in vitro using paired, human, macroscopically disease matched, carotid atheroma tissue biopsies obtained from five patients undergoing carotid endarterectomy. A 4-day incubation with specific Tn-C blocking antibodies (Abs) increased secretion of TLR-4-associated cytokines, interleukin (IL)-8, IL-1β, tumour necrosis factor and C-C motif chemokine (CCL)3 and expression of TLR-4 in the tissue. These results suggest with Tn-C blockade another endogenous TLR-4 ligand upregulates TLR-4 expression and subsequent cytokine secretion. Titration of the Tn-C Abs also dose dependently increased secretion of IL-6, IL-8, IL-1β, and CCL3 in mixed, healthy, primary vascular cell culture. In summary, circulating concentrations of Tn-C are higher in patients with a recent history of atherosclerotic stroke and may play an anti-inflammatory role by reducing pro-inflammatory cytokine release from atheroma. © 2014 International Union of Biochemistry and Molecular Biology.

Alkhatatbeh M.J.,University of Newcastle | Alkhatatbeh M.J.,Hunter Medical Research Institute | Enjeti A.K.,Hunter Medical Research Institute | Enjeti A.K.,Hunter Haematology Research Group | And 5 more authors.
Nutrition and Diabetes | Year: 2013

OBJECTIVE: Elevated plasma levels of the fatty acid transporter, CD36, have been shown to constitute a novel biomarker for type 2 diabetes mellitus (T2DM). We recently reported such circulating CD36 to be entirely associated with cellular microparticles (MPs) and aim here to determine the absolute levels and cellular origin(s) of these CD36+MPs in persons with T2DM. DESIGN: An ex vivo case-control study was conducted using plasma samples from 33 obese individuals with T2DM (body mass index (BMI)=39.9±6.4 kgm-2; age=57±9 years; 18 male:15 female) and age- and gender-matched lean and obese non-T2DM controls (BMI=23.6±1.8 kgm-2 and 33.5±5.9 kgm-2, respectively). Flow cytometry was used to analyse surface expression of CD36 together with tissue-specific markers: CD41, CD235a, CD14, CD105 and phosphatidyl serine on plasma MPs. An enzyme-linked immunosorbent assay was used to quantify absolute CD36 protein concentrations. RESULTS: CD36+MP levels were significantly higher in obese people with T2DM (P<0.00001) and were primarily derived from erythrocytes (CD235a+ =35.8±14.6%); although this did not correlate with haemoglobin A 1c. By contrast, the main source of CD36+MPs in non-T2DM individuals was endothelial cells (CD105+ =40.9±8.3% and 33.9±8.3% for lean and obese controls, respectively). Across the entire cohort, plasma CD36 protein concentration varied from undetectable to 22.9 μgml-1 and was positively correlated with CD36+MPs measured by flow cytometry (P=0.0006) but only weakly associated with the distribution of controls and T2DM (P=0.021). Multivariate analysis confirmed that plasma CD36+MP levels were a much better biomarker for diabetes than CD36 protein concentration (P=0.009 vs P=0.398, respectively). CONCLUSIONS: Both the levels and cellular profile of CD36+MPs differ in T2DM compared with controls, suggesting that these specific vesicles could represent distinct biological vectors contributing to the pathology of the disease. © 2013 Macmillan Publishers Limited All rights reserved.

Isbister G.K.,University of Newcastle | Isbister G.K.,A+ Network | Buckley N.A.,A+ Network | Buckley N.A.,University of New South Wales | And 6 more authors.
Journal of Thrombosis and Haemostasis | Year: 2013

Background: Venom-induced consumption coagulopathy (VICC) is a major effect of snake envenoming. Objectives: To investigate whether fresh frozen plasma (FFP) given after antivenom resulted in more rapid correction of coagulation. Patients/Methods: This was a multicenter open-label randomized controlled trial in patients with VICC of FFP vs. no FFP within 4 h of antivenom administration. Patients (> 2 years) recruited to the Australian snakebite project with VICC (International Normalized Ratio [INR] > 3) were eligible. Patients were randomized 2 : 1 to receive FFP or no FFP. The primary outcome was the proportion with an INR of < 2 at 6 h after antivenom administration. Secondary outcomes included time from antivenom administration to discharge, adverse effects, major hemorrhage, and death. Results: Of 70 eligible patients, 65 consented to be randomized: 41 to FFP, and 24 to no FFP. Six hours after antivenom administration, more patients randomized to FFP had an INR of < 2 (30/41 [73%] vs. 6/24 [25%]; absolute difference, 48%; 95% confidence interval 23-73%; P = 0.0002). The median time from antivenom administration to discharge was similar (34 h, range 14-230 h vs. 39 h, range 14-321 h; P = 0.44). Seven patients developed systemic hypersensitivity reactions after antivenom administration - two mild and one severe (FFP arm), and three mild and one severe (no FFP). One serious adverse event (intracranial hemorrhage and death) occurred in an FFP patient with pre-existing hypertension, who was hypertensive on admission, and developed a headache 6 h after FFP administration. Post hoc analysis showed that the median time from bite to FFP administration was significantly shorter for non-responders to FFP than for responders (4.7 h, interquartile range [IQR] 4.2-6.7 h vs. 7.3 h, IQR 6.1-8 h; P = 0.002). Conclusions: FFP administration after antivenom administration results in more rapid restoration of clotting function in most patients, but no decrease in discharge time. Early FFP administration (< 6-8 h) post-bite is less likely to be effective. © 2013 International Society on Thrombosis and Haemostasis.

Alkhatatbeh M.J.,University of Newcastle | Alkhatatbeh M.J.,Hunter Medical Research Institute | Mhaidat N.M.,Jordan University of Science and Technology | Enjeti A.K.,Hunter Medical Research Institute | And 5 more authors.
Journal of Thrombosis and Haemostasis | Year: 2011

Background:CD36 is a widely expressed cell surface receptor that binds lipoproteins, and its function has been implicated in many complications of the metabolic syndrome. A cell-free form of CD36, soluble CD36 (sCD36), has been reported in human plasma, found to be elevated in obesity and diabetes, and claimed as a marker of insulin resistance. Objective:To determine the nature of sCD36; in particular, whether sCD36 is truly soluble or, as hypothesized, is found as a component of circulating microparticles (MPs). Methods:Lipoproteins were fractionated by density gradient centrifugation, and plasma MPs were isolated by ultracentrifugation, size exclusion, and immunoprecipitation with CD36 detected by immunoblotting. MPs from plasma and activated platelets were analyzed by multicolor flow cytometry, with a DyLight-488 anti-CD36 conjugate in combination with antibodies against different cellular markers. Results:Cell-free plasma CD36 was not observed associated with lipoproteins and was not a proteolytic fragment; rather, it was associated with the plasma MP fraction, suggesting that sCD36 in the plasma of normal subjects is a product of circulating MPs. Cytometric and immunoblotting analyses of plasma from normal donors showed that these MPs were derived mainly from platelets. Analysis of in vitro activated platelets also showed that CD36 to be secreted in the form of MPs. Conclusions:sCD36 is not a proteolytic product, but rather is associated with a specific subset of circulating MPs that can readily be analysed. This finding will enable more specific investigations into the cellular source of the increased levels of plasma CD36 found in subjects with diabetes. © 2011 International Society on Thrombosis and Haemostasis.

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