Toll-Like Receptor 4-Dependent Platelet-Related Thrombosis in SARS-CoV-2 Infection.

BACKGROUND: SARS-CoV-2 is associated with an increased risk of venous and arterial thrombosis, but the underlying mechanism is still unclear. METHODS: We performed a cross-sectional analysis of platelet function in 25 SARS-CoV-2 and 10 healthy subjects by measuring Nox2 (NADPH oxidase 2)-derived oxidative stress and thromboxane B2, and investigated if administration of monoclonal antibodies against the S protein (Spike protein) of SARS-CoV-2 affects platelet activation. Furthermore, we investigated in vitro if the S protein of SARS-CoV-2 or plasma from SARS-CoV-2 enhanced platelet activation. RESULTS: Ex vivo studies showed enhanced platelet Nox2-derived oxidative stress and thromboxane B2 biosynthesis and under laminar flow platelet-dependent thrombus growth in SARS-CoV-2 compared with controls; both effects were lowered by Nox2 and TLR4 (Toll-like receptor 4) inhibitors. Two hours after administration of monoclonal antibodies, a significant inhibition of platelet activation was observed in patients with SARS-CoV-2 compared with untreated ones. In vitro study showed that S protein per se did not elicit platelet activation but amplified the platelet response to subthreshold concentrations of agonists and functionally interacted with platelet TLR4. A docking simulation analysis suggested that TLR4 binds to S protein via three receptor-binding domains; furthermore, immunoprecipitation and immunofluorescence showed S protein-TLR4 colocalization in platelets from SARS-CoV-2. Plasma from patients with SARS-CoV-2 enhanced platelet activation and Nox2-related oxidative stress, an effect blunted by TNF (tumor necrosis factor) α inhibitor; this effect was recapitulated by an in vitro study documenting that TNFα alone promoted platelet activation and amplified the platelet response to S protein via p47phox (phagocyte oxidase) upregulation. CONCLUSIONS: The study identifies 2 TLR4-dependent and independent pathways promoting platelet-dependent thrombus growth and suggests inhibition of TLR4. or p47phox as a tool to counteract thrombosis in SARS-CoV-2.

PAD4-Induced NETosis Via Cathepsin G-Mediated Platelet-Neutrophil Interaction in ChAdOx1 Vaccine-Induced Thrombosis-Brief Report.

BACKGROUND: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare syndrome characterized by platelet anti-PF4 (platelet-activating antiplatelet factor 4)-related thrombosis. Platelet-neutrophil interaction has been suggested to play a role, but the underlying mechanism has not been fully elucidated. METHODS: The study included 10 patients with VITT after ChAdOx1 (chimpanzee adenovirus Oxford 1) nCoV-19 (Oxford-AstraZeneca) vaccine administration, 10 patients with ischemic stroke (IS), 10 patients with acute deep vein thrombosis, and 10 control subjects in whom blood levels of neutrophil extracellular traps (NETs), soluble TF (tissue factor), and thrombin generation were examined. Furthermore, we performed in vitro studies comparing the effect of serum from patients and controls on NETs formation. Finally, immunohistochemistry was performed in cerebral thrombi retrieved from a patients with VITT and 3 patients with IS. RESULTS: Compared with patients with IS, patients with deep vein thrombosis, controls, and patients with VITT had significantly higher blood values of CitH3 (citrullinated histone H3), soluble TF, D-dimer, and prothrombin fragment 1+2 (P<0.0001). Blood CitH3 significantly correlated with blood soluble TF (Spearman rank correlation coefficient=0.7295; P=0.0206) and prothrombin fragment 1+2 (Spearman rank correlation coefficient=0.6809; P<0.0350) in patients with VITT. Platelet-neutrophil mixture added with VITT plasma resulted in higher NETs formation, soluble TF and thrombin generation, and platelet-dependent thrombus growth under laminar flow compared with IS and deep vein thrombosis plasma; these effects were blunted by PAD4 (protein arginine deiminase 4) and cathepsin G inhibitors, anti-FcγRIIa (Fc receptor for IgG class IIa), and high doses of heparin. Immunohistochemistry analysis showed a more marked expression of PAD4 along with more diffuse neutrophil infiltration and NETs formation as well as TF and cathepsin expression in VITT thrombus compared with thrombi from patients with IS. CONCLUSIONS: Patients with VITT display enhanced thrombogenesis by PAD4-mediated NETs formation via cathepsin G-mediated platelet/neutrophil interaction.

Oleuropein, a Component of Extra Virgin Olive Oil, Improves Liver Steatosis and Lobular Inflammation by Lipopolysaccharides-TLR4 Axis Downregulation.

Gut-dysbiosis-induced lipopolysaccharides (LPS) translocation into systemic circulation has been suggested to be implicated in nonalcoholic fatty liver disease (NAFLD) pathogenesis. This study aimed to assess if oleuropein (OLE), a component of extra virgin olive oil, lowers high-fat-diet (HFD)-induced endotoxemia and, eventually, liver steatosis. An immunohistochemistry analysis of the intestine and liver was performed in (i) control mice (CTR; n = 15), (ii) high-fat-diet fed (HFD) mice (HFD; n = 16), and (iii) HFD mice treated with 6 µg/day of OLE for 30 days (HFD + OLE, n = 13). The HFD mice developed significant liver steatosis compared to the controls, an effect that was significantly reduced in the HFD + OLE-treated mice. The amount of hepatocyte LPS localization and the number of TLR4+ macrophages were higher in the HFD mice in the than controls and were lowered in the HFD + OLE-treated mice. The number of CD42b+ platelets was increased in the liver sinusoids of the HFD mice compared to the controls and decreased in the HFD + OLE-treated mice. Compared to the controls, the HFD-treated mice showed a high percentage of intestine PAS+ goblet cells, an increased length of intestinal crypts, LPS localization and TLR4+ expression, and occludin downregulation, an effect counteracted in the HFD + OLE-treated mice. The HFD-fed animals displayed increased systemic levels of LPS and zonulin, but they were reduced in the HFD + OLE-treated animals. It can be seen that OLE administration improves liver steatosis and inflammation in association with decreased LPS translocation into the systemic circulation, hepatocyte localization of LPS and TLR4 downregulation in HFD-induced mouse model of NAFLD.

Endothelial dysfunction, oxidative stress and low-grade endotoxemia in COVID-19 patients hospitalised in medical wards.

BACKGROUND: Endothelial dysfunction, assessed by flow-mediated dilation (FMD), is related to poor prognosis in patients with COVID-19 pneumonia (CP). In this study, we explored the interplay among FMD, NADPH oxidase type 2 (NOX-2) and lipopolysaccharides (LPS) in hospitalised patients with CP, community acquired pneumonia (CAP) and controls (CT). METHODS: We enrolled 20 consecutive patients with CP, 20 hospitalised patients with CAP and 20 CT matched for sex, age, and main cardiovascular risk factors. In all subjects we performed FMD and collected blood samples to analyse markers of oxidative stress (soluble Nox2-derived peptide (sNOX2-dp), hydrogen peroxide breakdown activity (HBA), nitric oxide (NO), hydrogen peroxide (H2O2)), inflammation (TNF-α and IL-6), LPS and zonulin levels. RESULTS: Compared with controls, CP had significant higher values of LPS, sNOX-2-dp, H2O2,TNF-α, IL-6 and zonulin; conversely FMD, HBA and NO bioavailability were significantly lower in CP. Compared to CAP patients, CP had significantly higher levels of sNOX2-dp, H2O2, TNF-α, IL-6, LPS, zonulin and lower HBA. Simple linear regression analysis showed that FMD inversely correlated with sNOX2-dp, H2O2, TNF-α, IL-6, LPS and zonulin; conversely FMD was directly correlated with NO bioavailability and HBA. Multiple linear regression analysis highlighted LPS as the only predictor of FMD. CONCLUSION: This study shows that patients with COVID-19 have low-grade endotoxemia that could activate NOX-2, generating increased oxidative stress and endothelial dysfunction.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) levels in primary antiphospholipid syndrome. The multicenter ATHERO-APS study.

BACKGROUND: The proprotein convertase subtilisin/kexin type 9 (PCSK9) is emerging as a novel cardiovascular risk factor. Levels of PCSK9 in thrombotic primary antiphospholipid syndrome (PAPS) have never been investigated. METHODS: Cross sectional comparison of baseline characteristics of 91 PAPS patients enrolled in the multicenter prospective ATHERO-APS cohort study. PCSK9 levels were categorized into tertiles and the association with arterial and recurrent thrombosis were assessed by univariable and multivariable logistic regression analysis. RESULTS: Median age was 51 years and 71.4% (n = 65) were women. Overall, 33% (n = 30) experienced an arterial event while 31% (n = 28) had recurrent thrombotic events. Median PCSK9 levels were 1243 (1100-1650) pg/ml. Patients in the third PCSK9 tertile (>1458 pg/ml) showed a higher prevalence of dyslipidemia, lupus anticoagulant positivity and a history of previous arterial and recurrent thrombosis than patients in the first and second tertile. PCSK9 levels were higher in arterial than venous thrombosis (1502 vs. 1180 pg/ml, p = 0.002), and in patients with recurrent vs isolated thrombosis (1680 vs. 1150 pg/m, p < 0.001). High plasma PCSK9 levels were associated with a 4-fold increase risk for arterial events and with a 10-fold increase risk for recurrent thrombosis after adjustment for confounding factors. CONCLUSION: These preliminary data suggest that PCSK9 levels are increased in PAPS patients with arterial and recurrent thrombosis. Its role as a possible therapeutic target in PAPS needs further studies.

Corticosteroid use, myocardial injury and in-hospital cardiovascular events in patients with community-acquired pneumonia.

BACKGROUND AND PURPOSE: Corticosteroids are often prescribed to community-acquired pneumonia (CAP) patients, but the relationship with major cardiovascular events (MACEs) is unclear. EXPERIMENTAL APPROACH: 541 CAP patients were recruited (334 males, mean age 71.9 ± 16.2 years). High-sensitivity troponin T (hs-cTnT) was measured at admission, during the hospital stay and at discharge. MACE occurrence was registered during a long-term follow-up. KEY RESULTS: Overall, 318 patients (59%) showed hs-cTnT elevation >99th percentile (>0.014 µg/L). Age, heart failure and the increasing quintiles of hs-cTnT (hazard ratio [HR] 2.16, 95% confidence interval [CI] 1.82-2.58, P < .001) predicted MACEs. Among patients with hs-cTnT >0.014 µg/L at admission, 102 patients (31%) were on corticosteroids and showed lower hs-cTnT increase (P = .021), (NADPH) oxidase-2 (Nox2) activation (P = .005) and incidence of MACEs than untreated ones (HR 0.64, 95% CI 0.41-0.97, P = .038); no effect of corticosteroids on MACEs was observed in CAP patients with normal troponin. In vitro study showed that glucocorticoids have an antioxidant effect via downregulation of Nox2 activity. CONCLUSION AND IMPLICATIONS: The study provides evidence that corticosteroid use is associated with lower increase of hs-cTnT and incidence of MACEs in CAP patients.

Impact of chronic use of heat-not-burn cigarettes on oxidative stress, endothelial dysfunction and platelet activation: the SUR-VAPES Chronic Study.

Tobacco habit still represents the leading preventable cause of morbidity and mortality worldwide. Heat-not-burn cigarettes (HNBCs) are considered as an alternative to traditional combustion cigarettes (TCCs) due to the lack of combustion and the absence of combustion-related specific toxicants. The aim of this observational study was to assess the effect of HNBC on endothelial function, oxidative stress and platelet activation in chronic adult TCC smokers and HNBC users. The results showed that both HNBC and TCC display an adverse phenotype in terms of endothelial function, oxidative stress and platelet activation. Future randomised studies are strongly warranted to confirm these data.

Proprotein Convertase Subtilisin Kexin Type 9 Inhibitors Reduce Platelet Activation Modulating ox-LDL Pathways.

Background: Proprotein convertase subtilisin kexin type 9 inhibitors (PCSK9i) lower LDL-cholesterol and slow atherosclerosis preventing cardiovascular events. While it is known that circulating PCSK9 enhances platelet activation (PA) and that PCSK9i reduce it, the underlying mechanism is not still clarified. Methods: In a multicenter before-after study in 80 heterozygous familial hypercholesterolemia (HeFH) patients on treatment with maximum tolerated statin dose ± ezetimibe, PA, soluble-NOX2-derived peptide (sNOX2-dp), and oxidized-LDL (ox-LDL) were measured before and after six months of PCSK9i treatment. In vitro study investigates the effects of plasma from HeFH patients before and after PCK9i on PA in washed platelets (wPLTs) from healthy subjects. Results: Compared to baseline, PCSK9i reduced the serum levels of LDL-c, ox-LDL, Thromboxane (Tx) B2, sNOX2-dp, and PCSK9 (p < 0.001). The decrease of TxB2 correlates with that of ox-LDL, while ox-LDL reduction correlated with PCSK9 and sNOX2-dp delta. In vitro study demonstrated that wPLTs resuspended in plasma from HeFH after PCSK9i treatment induced lower PA and sNOX2-dp release than those obtained using plasma before PCSK9i treatment. This reduction was vanished by adding ox-LDL. ox-LDL-induced PA was blunted by CD36, LOX1, and NOX2 inhibition. Conclusions: PCSK9i treatment reduces PA modulating NOX2 activity and in turn ox-LDL formation in HeFH patients.

Gut-derived lipopolysaccharides increase post-prandial oxidative stress via Nox2 activation in patients with impaired fasting glucose tolerance: effect of extra-virgin olive oil.

PURPOSE: Post-prandial phase is characterized by enhanced oxidative stress but the underlying mechanism is unclear. We investigated if gut-derived lipopolysaccharide (LPS) is implicated in this phenomenon and the effect of extra virgin olive oil (EVOO) in patients with impaired fasting glucose (IFG). METHODS: This is a randomized cross-over interventional study including 30 IFG patients, to receive a lunch with or without 10 g of EVOO. Serum LPS, Apo-B48, markers of oxidative stress such as oxidized LDL (oxLDL) and soluble Nox2-derived peptide (sNox2-dp), a marker of nicotinamide-adenine-dinucleotide-phosphate oxidase isoform Nox2 activation, and plasma polyphenols were determined before, 60 and 120 min after lunch. RESULTS: In patients not given EVOO oxidative stress as assessed by sNox2-dp and oxLDL significantly increased at 60 and 120 min concomitantly with an increase of LPS and Apo-B48. In these patients, changes of LPS were correlated with Apo-B48 (Rs = 0.542, p = 0.002) and oxLDL (Rs = 0.463, p = 0.010). At 120 min, LPS (ß - 15.73, p < 0.001), Apo-B48 (ß - 0.14, p = 0.004), sNox2-dp (ß - 5.47, p = 0.030), and oxLDL (ß - 42.80, p < 0.001) significantly differed between the two treatment groups. An inverse correlation was detected between polyphenols and oxLDL (R - 0.474, p < 0.005). In vitro study showed that LPS, at the same concentrations found in the human circulation, up-regulated Nox2-derived oxidative stress via interaction with Toll-like receptor 4. CONCLUSIONS: Post-prandial phase is characterized by an oxidative stress-related inflammation potentially triggered by LPS, a phenomenon mitigated by EVOO administration.

Low-grade endotoxemia and platelet activation in cirrhosis.

Patients with cirrhosis may display impaired or enhanced platelet activation, but the reasons for these equivocal findings are unclear. We investigated if bacterial lipopolysaccharide (LPS) is implicated in platelet activation. In a cross-sectional study, conducted in an ambulatory care clinic and hospital, comparing 69 cirrhosis patients and 30 controls matched for sex, age, and atherosclerotic risk factors, serum levels of LPS, soluble cluster of differentiation 40 ligand and p-selectin (two markers of platelet activation), and zonulin (a marker of gut permeability) were investigated. Ex vivo and in vitro studies were also performed to explore the effect of LPS on platelet activation. Compared to controls, cirrhosis patients displayed higher serum levels of LPS (6.0 [4.0-17.5] versus 57.4 [43.4-87.2] pg/mL, P < 0.0001), soluble cluster of differentiation 40 ligand (7.0 ± 2.2 versus 24.4 ± 13.3 ng/mL, P < 0.0001), soluble p-selectin (14.2 ± 4.05 versus 33.2 ± 15.2 ng/mL, P < 0.0001), and zonulin (1.87 ± 0.84 versus 2.54 ± 0.94 ng/mL, P < 0.006). LPS significantly correlated with zonulin (r = 0.45, P < 0.001). Ex vivo studies showed that platelets from cirrhosis patients were more responsive to the agonists independently from platelet count; this phenomenon was blunted by incubation with an inhibitor of Toll-like receptor 4. In vitro study by normal platelets showed that LPS alone (50-150 pg/mL) did not stimulate platelets but amplified platelet response to the agonists; Toll-like receptor 4 inhibitor blunted this effect. CONCLUSION: LPS may be responsible for platelet activation and potentially contributes to thrombotic complications occurring in cirrhosis. (Hepatology 2017;65:571-581).

Oleuropein, a component of extra virgin olive oil, lowers postprandial glycaemia in healthy subjects.

AIMS: Extra virgin olive oil lowers postprandial glycaemia. We investigated if oleuropein, a component of extra virgin olive oil, exerts a similar effect on postprandial glycaemia and the underlying mechanism. METHODS: Twenty healthy subjects were randomly allocated in a cross-over design to 20 mg oleuropein or placebo immediately before lunch. Postprandial glycaemia along with blood insulin, dipeptidyl-peptidase-4 (DPP-4) and glucagon-like peptide-1 and oxidative stress, which included soluble NADPH oxidase-derived peptide activity (sNox2-dp), 8-iso-prostaglandin-2α and platelet p47phox phosphorylation, were analysed before and 2 h after meal. RESULTS: After 2 h, subjects who assumed oleuropein had significantly lower blood glucose, DPP-4 activity and higher insulin and glucagon-like peptide-1 compared to placebo. Furthermore, sNox2-dp, 8-iso-PGF2α and platelet p47phox phosphorylation were significantly lower in oleuropein- compared to placebo-treated subjects. DPP-4 significantly correlated with sNox2-dp [Spearman's rho (Rs) = 0.615; P < 0.001], p47phox phosphorylation (Rs = 0.435; P < 0.05) and 8-iso- prostaglandin-2α (Rs = 0.33; P < 0.05). In vitro study demonstrated that hydroxytyrosol, a metabolite of oleuropein, significantly reduced p47phox phosphorylation and isoprostane formation. CONCLUSIONS: These findings indicate that oleuropein improves postprandial glycaemic profile via hampering Nox2-derived oxidative stress.

Gut-derived endotoxin stimulates factor VIII secretion from endothelial cells. Implications for hypercoagulability in cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis display enhanced blood levels of factor VIII, which may result in harmful activation of the clotting system; however, the underlying mechanism is unknown. METHODS: We performed a cross-sectional study in patients with cirrhosis (n=61) and matched controls (n=61) comparing blood levels of factor VIII, von Willebrand factor (vWf), lipopolysaccharide (LPS) and positivity for Escherichia coli DNA. Furthermore, we performed an in vitro study to investigate if LPS, in a concentration range similar to that found in the peripheral circulation of cirrhotic patients, was able to elicit factor VIII secretion from human umbilical vein endothelial cells (HUVEC). RESULTS: Patients with cirrhosis displayed higher serum levels of LPS (55.8 [42.2-79.9] vs. 23.0 [7.0-34.0]pg/ml, p<0.001), factor VIII (172.0 [130.0-278.0] vs. 39.0 [26.0-47.0]U/dl, p<0.0001), vWf (265.0 [185.0-366.0] vs. 57.0 [48.0-65.0]U/dl, p<0.001) and positivity for Escherichia coli DNA (88% vs. 3%, p<0.001, n=34) compared to controls. Serum LPS correlated significantly with factor VIII (r=0.80, p<0.001) and vWf (r=0.63, p<0.001). Only LPS (beta-coefficient=0.70, p<0.0001) independently predicted factor VIII levels. The in vitro study showed that LPS provoked factor VIII and vWf release from HUVEC via formation and secretion of Weibel-Palade bodies, a phenomenon blunted by pre-treating HUVEC with an inhibitor of Toll-like receptor 4. CONCLUSIONS: The study provides the first evidence that LPS derived from gut microbiota increases the systemic levels of factor VIII via stimulating its release by endothelial cells. Lay summary: Cirrhosis is associated with thrombosis in portal and systemic circulation. Enhanced levels of factor VIII have been suggested to play a role but the underlying mechanism is still unclear. Here we show that patients with cirrhosis display a concomitant increase of factor VIII and lipopolysaccharide (LPS) from Escherichia coli and suggest that LPS contributes to the release of factor VIII from endothelial cells.

Anti Xa oral anticoagulants inhibit in vivo platelet activation by modulating glycoprotein VI shedding.

Anti Xa non-vitamin K oral anticoagulants (anti Xa NOACs) seem to possess antiplatelet effect in vitro, but it is unclear if this occurs also in vivo. Aim of the study was to compare the effect on platelet activation of two anti Xa NOACs, namely apixaban and rivaroxaban, to warfarin, and to investigate the potential underlying mechanism by evaluating soluble glycoprotein GPVI (sGPVI), a protein involved in platelet activation. We performed a cross-sectional including AF patients treated with warfarin (n=30), or apixaban 10mg/day (n=40), or rivaroxaban 20mg/day (n=40). Patients were balanced for sex, age and cardiovascular risk factors. Platelet activation by urinary excretion of 11-dehydro-thromboxane (Tx) B2 and soluble GPVI (sGPVI) were analysed at baseline and after 3 months of treatment. Baseline TxB2 value was 155.2±42.7ng/mg creatinine. The 3 months-variation of urinary excretion of TxB2 was -6.5% with warfarin (p=0.197), -29% with apixaban (p<0.001) and -31% with rivaroxaban (p<0.001). Use of anti Xa NOACs was independently associated to the variation of urinary TxB2 (B: -0.469, p<0.001), after adjustment for clinical characteristics; sGPVI was significantly lower in patients treated with NOACs at 3 months (p<0.001), while only a trend for the warfarin group (p=0.116) was observed. The variation of sGPVI was correlated with that of TxB2 in the NOACs group (Rs: 0.527, p<0.001). In 15 patients (5 per each group) platelet recruitment was significantly lowered at 3 months by NOACs (p<0.001), but not by warfarin. The study provides evidence that anti Xa NOACs significantly inhibit urinary TxB2 excretion compared to warfarin, suggesting that NOACs possess antiplatelet property.

Low-grade endotoxemia and clotting activation in the early phase of pneumonia.

BACKGROUND AND OBJECTIVE: Community-acquired pneumonia (CAP) is associated with an increased risk of arterial and venous thrombosis but the underlying pathophysiological mechanisms are still unclear. We investigated if, in patients with CAP, a pro-thrombotic state does exist and its relationship with serum levels of endotoxins. METHODS: A total of 104 consecutive patients with CAP were prospectively recruited and followed up until discharge. At admission and at discharge, serum endotoxins, systemic markers of clotting activation and zonulin, a marker of gut permeability, were analysed. Hospitalized patients matched for gender, age and comorbidities but without infections were used as control. RESULTS: At admission, CAP patients showed higher plasma levels of F1+2 , a marker of thrombin generation (P = 0.023), and lower levels of protein C (PC; P < 0.001) and activated PC (aPC) (P < 0.001) compared with controls. At discharge, plasma levels of both PC and aPC significantly increased while F1+2 significantly decreased (P < 0.001). Baseline serum endotoxins and zonulin were higher in CAP patients than controls (P < 0.001) and significantly decreased at discharge; a significant correlation between serum endotoxins and zonulin was detected (R = 0.575; P < 0.001) CONCLUSION: This study provides the first evidence that CAP patients disclose an ongoing pro-thrombotic state and suggests a role for endotoxemia in determining enhanced thrombin generation.

Urinary 11-dehydro-thromboxane B2 is associated with cardiovascular events and mortality in patients with atrial fibrillation.

BACKGROUND: Patients with nonvalvular atrial fibrillation (AF) show high residual cardiovascular (CV) risk despite oral anticoagulants. Urinary 11-dehydro-thromboxane B2 (TxB2) is associated with an increased risk of CV events (CVEs), but its predictive value in patients with anticoagulated AF is unknown. METHODS: A prospective single-center cohort study, including 837 patients with AF, was conducted. Mean time of follow-up was 30.0 months, yielding 2,062 person-years of observation. Urinary 11-dehydro-TxB2 was measured at baseline. The primary end point was the occurrence of a CVE including fatal/nonfatal myocardial infarction and ischemic stroke, transient ischemic attack, cardiac revascularization, and CV death. RESULTS: Mean age of patients was 73.1 years, and 43.6% were women. Median 11-dehydro-TxB2 levels were 100 (interquartile range 50-187) ng/mg of urinary creatinine. Overall, the anticoagulation control was adequate (63.9% of mean time in therapeutic range). A CVE occurred in 99 (11.8%) patients, and 55 were CV deaths. At baseline, 11-dehydro-TxB2 levels were higher in patients with a CVE compared with those without (186 [107-400] vs 98 [52-170], P < .001). An increased rate of CVEs (log-rank test, P < .001) and CV deaths (P < .001) was observed across tertiles of 11-dehydro-TxB2. Cardiovascular events were associated with age (hazard ratios [HR] 1.72 per 1 SD, 95% CI 1.33-2.21, P < .001), diabetes mellitus (HR 1.89, 95% CI 1.20-2.96, P = .005), heart failure (HR 1.60, 95% CI 1.01-2.54, P = .044), history of stroke/transient ischemic attack (HR 1.96, 95% CI 1.25-3.06, P = .003), and 11-dehydro-TxB2 (HR 1.64 per 1 SD, 95% CI 1.42-1.89, P < .001). CONCLUSIONS: Urinary 11-dehydro-TxB2 levels are associated with a residual risk of CVEs and CV mortality in patients with AF despite anticoagulant treatment.

Relationship between Mediterranean diet and time in therapeutic range in atrial fibrillation patients taking vitamin K antagonists.

AIMS: It is unclear if atrial fibrillation (AF) patients treated with oral vitamin K antagonists (VKAs) must follow a specific diet to avoid interference with anticoagulation. The aim of this study was to assess if Mediterranean diet (Med-Diet) may affect quality of anticoagulation, as expressed by the time in therapeutic range (TTR). METHODS AND RESULTS: A prospective observational study including 553 non-valvular AF patients. Time in therapeutic range was calculated for all patients treated with VKAs, and adherence to Med-Diet was evaluated with a validated nine-item dietary questionnaire. Cardiovascular events (CVEs), such as cardiovascular death and fatal/non-fatal stroke or myocardial infarction, and bleedings were recorded. The median follow-up was 31.6 months. The median number of international normalized ratios for each patient was 63.0 (35.0-98.0) and 38 730 blood samples were analysed. In the whole cohort, the mean TTR was 65.5 ± 17.8%. The mean Med-Diet score was 5.19 ± 1.6, with frequent use of olive oil (90.1%), fruits (88.4%), and vegetables (69.3%) and low meat intake (71.2%). There were no differences among tertiles of Med-Diet score regarding TTR. A multivariable linear regression analysis showed that diabetes (ß: -0.105, P = 0.015) and the use of angiotensin converting enzyme inhibitor/angiotensin receptor blockers (ß: 0.153, P < 0.001) were associated with TTR. Compared with those without, AF patients with a CVE had significantly lower TTR (65.9 ± 17.9 vs. 59.6 ± 15.9, P = 0.029) and Med-Diet score (5.2 ± 1.5 vs. 4.4 ± 1.9, P = 0.004). A reduction of CVE was observed for each point of the Med-Diet score (hazard ratio 0.790, P = 0.017). CONCLUSION: In our cohort of AF patients, Med-Diet is not associated with changes in TTR, and thus can be recommended for AF patients who are taking VKAs.

NOX2-generated oxidative stress is associated with severity of ultrasound liver steatosis in patients with non-alcoholic fatty liver disease.

BACKGROUND: Chronic oxidative stress is one of the key mechanisms responsible for disease progression in non-alcoholic fatty liver disease. However, so far, few studies reported increased circulating levels of oxidative stress markers in patients with non-alcoholic fatty liver and no study has been performed with newer markers of systemic oxidative stress. The aim was to assess the relationship between urinary 8-iso-prostaglandin F2α and serum soluble NOX2-derived peptide and the severity of liver steatosis in subjects with non-alcoholic fatty liver. METHODS: The study was performed in 264 consecutive patients referred for suspected metabolic disease. Steatosis was defined according to Hamaguchi ultrasonographic criteria. Oxidative stress was assessed by urinary 8-iso- prostaglandin F2α and serum soluble NOX2-derived peptide levels. RESULTS: Patients with non-alcoholic fatty liver had higher (p < 0.001) mean values of urinary 8-iso-PGF2α and of serum soluble NOX2-derived peptide, alanine aminotransferase, Cytokeratin-18 and homeostasis model of insulin resistance and lower values of serum adiponectin as compared to those without. Prevalence of metabolic syndrome and of its clinical features was significantly higher in patients with non-alcoholic fatty liver. Same findings were also observed after the exclusion of obese subjects, or subjects with diabetes or with metabolic syndrome and in those not taking statin medication. In addition, the levels of urinary 8-iso-PGF2α were independent predictors of non-alcoholic fatty liver and a strong association of urinary 8-iso-PGF2α and of serum soluble NOX2-derived peptide with the severity of steatosis at ultrasound was also observed. CONCLUSIONS: We demonstrated increased markers of oxidative stress in subjects with non-alcoholic fatty liver. Urinary 8-iso-PGF2α and serum soluble NOX2-derived peptide levels were independent from obesity, diabetes and metabolic syndrome and increased with the severity of liver steatosis at ultrasound.

Low-grade endotoxemia is associated with cardiovascular events in community-acquired pneumonia.

OBJECTIVES: Community-acquired pneumonia (CAP) is associated with low-grade endotoxemia but its relationship with cardiovascular events (CVE) has not been investigated. METHODS: We evaluated the incidence of CVE including myocardial infarction, stroke, and cardiovascular death in 523 adult patients hospitalized for CAP. Serum lipopolysaccharide (LPS) and zonulin, a marker of gut permeability, were analyzed in the cohort, that was followed-up during hospitalization and up to 43 months thereafter. RESULTS: During the hospital-stay, 55 patients experienced CVE with a progressive increase from the lowest (0.6%) to highest LPS tertile (23.6%, p < 0.001). Logistic regression analyses showed that higher LPS tertile was independently associated with CVE; LPS significantly correlated with age, hs-CRP and zonulin. In a sub-group of 23 CAP patients, blood E. coli DNA was higher in patients compared to 24 controls and correlated with LPS. During the long-term follow-up, 102 new CVE were registered; the highest tertile of LPS levels was associated with incident CVE; Cox regression analysis showed that LPS tertiles, age, history of CHD, and diabetes independently predicted CVE. CONCLUSIONS: In CAP low-grade endotoxemia is associated to short- and long-term risk of CVE. Further study is necessary to assess if lowering LPS by non-absorbable antibiotics may result in improved outcomes.

Impact of heat-not-burn cigarette passive smoking on children's oxidative stress, endothelial and platelet function.

Growing global use of heat-not-burn cigarettes (HNBC) prompts investigation. Prior studies assessed HNBC's effects on cardiovascular health, revealing heightened oxidative stress, platelet activation, and endothelial dysfunction. However, limited understanding exists regarding passive smoking's impact on children exposed to HNBC. This study aims to assess levels of oxidative stress, endothelial and platelet function among children exposed to passive smoke from HNBC, traditional tobacco (TT) cigarettes and unexposed subjects. Seventy-eight children (2-18 years) were divided into three groups: HNBC passive smokers (n = 26), TT cigarette exposed (n = 26), and control (CNT) group (n = 26, unexposed). Oxidative stress was evaluated by serum NADPH oxidase-2 (NOX2) activity, assessed by soluble Nox2-derived peptide (sNOX2-dp), isoprostanes, hydrogen peroxide (H2O2) production, hydrogen break-down activity (HBA) and NO bioavailability. Endothelial function was assessed by brachial flow-mediated dilation (FMD). Platelet function was evaluated by soluble CD40 ligand (sCD40L), soluble P-selectin (sP-selectin) and thrombus formation by T-TAS analysis. Passive smoking-exposed children (both HNBC and TT) exhibited significantly increased serum sNOX2-dp, isoprostanes, H2O2, sCD40L sP-selectin and thrombus formation versus controls. Conversely, exposed children displayed reduced brachial FMD and serum NO bioavailability. No significant differences were found between children exposed to passive smoking of HNBC vs TT. Multivariable regression linked sNOX2 (standardized coefficient ß: 0.284; SE: 0.040; p = 0.01) and H2O2 (standardized coefficient ß: 0.243; SE: 0.0; p = 0.02) as independent predictors of FMD, and isoprostanes (standardized coefficient ß:0.388; SE: 0.022; p < 0.001) and serum cotinine (standardized coefficient ß:0.270; SE: 0.048; p = 0.01) with sNOX2-dp levels. Exposure to HNBC smoke heightened oxidative stress, endothelial dysfunction, platelet activation, and thrombus formation in children. Findings suggest avenues for interventions to curb childhood passive smoking exposure.