Vitamin C inhibits platelet expression of CD40 ligand

Upon stimulation with agonists, platelets express CD40 ligand (CD40L), a transmembrane protein implicated in the initiation and progression of atherosclerotic disease. We have recently discovered that oxidative stress plays a major role in platelet CD40L expression. In this study, we sought to determine whether vitamin C, a known antioxidant, is able to influence platelet CD40L expression. In vitro experiments were done by stimulating platelets with collagen in the presence or absence of vitamin C (50-100 mu M) or vehicle as control. An in vivo study was done in 10 healthy subjects who were randomized to intravenous infusion of placebo or 1 g vitamin C for 45 min in a crossover design. At the end of infusion platelet CD40L and O2- were measured. The in vitro study demonstrated that vitamin C dose dependently inhibited platelet CD40L expression without affecting agonist-induced platelet aggregation. In subjects treated with placebo no changes of platelet CD40L and O2- were observed; conversely, vitamin C infusion caused a significant and parallel decrease of platelet O2- (-70%, P < 0.001) and CD40L (-68%, P < 0.001). Platelet aggregation was not modified by either treatment. This study suggests that water-soluble antioxidants, which scavenge superoxide radicals, may reduce platelet CD40L expression. (c) 2005 Elsevier Inc. All rights reserved

Imbalance between nitric oxide generation and oxidative stress in patients with peripheral arterial disease: Effect of an antioxidant treatment

BackgroundNitric oxide (NO), a potent vasodilator produced by endothelial cells, is reduced in patients with peripheral arterial disease (PAD), but the mechanism has not been fully elucidated. Because NO is rapidly inactivated by superoxide anion, we speculated that enhanced oxidative stress could lower NO generation. The aim of our study was to investigate if an imbalance between oxidative stress and NO does exist in patients with PAD and if an increase of NO formation could be achieved by an antioxidant treatment.MethodsIn a first study, serum levels of nitrite and nitrate (NOx), markers of NO generation, and 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative stress and maximal walking distance (MWD), were measured in 40 PAD patients and 40 controls. In a second study, 10 PAD patients were randomly allocated in a crossover design to intravenous propionyl-L-carnitine (6 g/day) or placebo for 7 days, with a washout of 30 days between the two phases of the trial. Serum levels of NOx and 8-OHdG were measured before and after the study.ResultsCompared with controls, serum levels of 8-OHdG (mean ± SD) were significantly increased in PAD patients (4.4 ± 3.1 ng/mL vs 2.4 ± 1.2 ng/mL; P < .001), and serum levels of NOx were significantly decreased (11.6 ± 6 μM vs 17 ± 6.1 μM; P < .001). Levels of 8-OHdG and NOx were inversely correlated (r = −0.879; P < .001). Serum levels 8-OHdG were inversely correlated with MWD (r = −0.48, P = .002). The interventional trial showed no changes in the patients given placebo. Patients treated with propionyl-L-carnitine showed a significant increase of MWD from 101 ± 31 meters to 129 ± 35 meters (P = .007) and in NOx from 14.5 ± 4.5 μM to 17.1 ± 3.8 μM (P = .007). A significant decrease of 8-OHdG from 3.6 ± 1.1 ng/mL to 2.6 ± 1 ng/mL was also found (P = .005.)ConclusionsThis study suggests that in PAD patients, the reduction of NO generation could be dependent upon enhanced oxidative stress

Selenium in humans: which is the safe range of intake?

Selenium in humans: which is the safe range of intake

In vitro effects of interleukin (IL)-1 beta inhibition on the epithelial-to-mesenchymal transition (EMT) of renal tubular and hepatic stellate cells

BACKGROUND: The epithelial to mesenchymal transition (EMT) is a multi-factorial biological mechanism involved in renal and hepatic fibrosis and the IL-1 beta has been assumed as a mediator of this process although data are not exhaustive. Therefore, the aim of our study was to evaluate the role of this cytokine in the EMT of renal proximal tubular epithelial cells (HK-2) and stellate cells (LX-2) and the protective/anti-fibrotic effect of its inhibition by Canakinumab (a specific human monoclonal antibody targeted against IL-1beta). METHODS: Both cell types were treated with IL-1 beta (10 ng/ml) for 6 and 24 h with and without Canakinumab (5 \u3bcg/ml). As control we used TGF-beta (10 ng/ml). Expression of EMT markers (vimentin, alpha-SMA, fibronectin) were evaluated through western blotting and immunofluorescence. Genes expression for matrix metalloproteinases (MMP)-2 was measured by Real-Time PCR and enzymatic activity by zymography. Cellular motility was assessed by scratch assay. RESULTS: IL-1 beta induced a significant up-regulation of EMT markers in both cell types and increased the MMP-2 protein expression and enzymatic activity, similarly to TGF-beta. Moreover, IL-1 beta induced a higher rate of motility in HK-2. Canakinumab prevented all these modifications in both cell types. CONCLUSIONS: Our results clearly demonstrate the role of IL-1 beta in the EMT of renal/stellate cells and it underlines, for the first time, the therapeutic potential of its specific inhibition on the prevention/minimization of organ fibrosis

Association Between NOX2-Mediated Oxidative Stress, Low-Grade Endotoxemia, Hypoalbuminemia, and Clotting Activation in COVID-19

Low-grade endotoxemia by lipopolysaccharide (LPS) has been detected in COVID-19 and could favor thrombosis via eliciting a pro-inflammatory and pro-coagulant state. The aim of this study was to analyze the mechanism accounting for low-grade endotoxemia and its relationship with oxidative stress and clotting activation thrombosis in COVID-19. We measured serum levels of sNOX2-dp, zonulin, LPS, D-dimer, and albumin in 175 patients with COVID-19, classified as having or not acute respiratory distress syndrome (ARDS), and 50 healthy subjects. Baseline levels of sNOX2- dp, LPS, zonulin, D-dimer, albumin, and hs-CRP were significantly higher in COVID-19 compared to controls. In COVID-19 patients with ARDS, sNOX2-dp, LPS, zonulin, D-dimer, and hs-CRP were significantly higher compared to COVID-19 patients without ARDS. Conversely, concentration of albumin was lower in patients with ARDS compared with those without ARDS and inversely associated with LPS. In the COVID-19 cohort, the number of patients with ARDS progressively increased according to sNOX2-dp and LPS quartiles; a significant correlation between LPS and sNOX2-dp and LPS and D-dimer was detected in COVID-19. In a multivariable logistic regression model, LPS/albumin levels and D-dimer predicted thrombotic events. In COVID-19 patients, LPS is significantly associated with a hypercoagulation state and disease severity. In vitro , LPS can increase endothelial oxidative stress and coagulation biomarkers that were reduced by the treatment with albumin. In conclusion, impaired gut barrier permeability, increased NOX2 activation, and low serum albumin may account for low-grade endotoxemia and may be implicated in thrombotic events in COVID-19

Direct-acting antivirals and hepatocellular carcinoma in chronic hepatitis C: A few lights and many shadows

With the introduction of direct-acting antiviral agents (DAA), the rate of sustained virological response (SVR) in the treatment of hepatitis C virus (HCV) has radically improved to over 95%. Robust scientific evidence supports a beneficial role of SVR after interferon therapy in the progression of cirrhosis, resulting in a decreased incidence of hepatocellular carcinoma (HCC). However, a debate on the impact of DAAs on the development of HCC is ongoing. This review aimed to analyse the scientific literature regarding the risk of HCC in terms of its recurrence and occurrence after the use of DAAs to eradicate HCV infection. Among 11 studies examining HCC occurrence, the de novo incidence rate ranged from 0 to 7.4% (maximum follow-up: 18 mo). Among 18 studies regarding HCC recurrence, the rate ranged from 0 to 54.4% (maximum "not well-defined" followup: 32 mo). This review highlights the major difficulties in interpreting data and reconciling the results of the included studies. These difficulties include heterogeneous cohorts, potential misclassifications of HCC prior to DAA therapy, the absence of an adequate control group, short follow-up times and different kinds of follow-up. Moreover, no clinical feature-based scoring system accounts for the molecular characteristics and pathobiology of the tumours. Nonetheless, this review does not suggest that there is a higher rate of de novo HCC occurrence or recurrence after DAA therapy in patients with previous HCV infection. \ua9 2018 The Author(s). Published by Baishideng Publishing Group Inc. All rights reserved

Hypoalbuminemia and Risk of Portal Vein Thrombosis in Cirrhosis

Background and Aims: Hypoalbuminemia, as defined by serum albumin (SA) levels ≤35 g/L, is associated to venous and arterial thrombosis in general population and in patients at risk of cardiovascular disease. It is unknown if SA ≤35 g/L is also associated to portal vein thrombosis (PVT) in cirrhosis. Methods: Cirrhotic patients enrolled in the Portal vein thrombosis Relevance On Liver cirrhosis: Italian Venous thrombotic Events Registry (PRO-LIVER) study (n = 753), were followed-up for 2 years to assess the risk of PVT, that was diagnosed by Doppler ultrasonography. Child-Pugh classes, Model for End-Stage Liver Disease score, presence of hepatocellular carcinoma and laboratory variables including SA, D-dimer, and high-sensitivity C-reactive protein (hs-CRP) were measured at baseline. Results: SA ≤35 g/L was detected in 52% of patients. A logistic multivariate regression analysis showed that higher Child-Pugh class, hepatocellular carcinoma and thrombocytopenia were significantly associated to SA ≤35 g/L. In a subgroup of patients where data regarding hs-CRP and D-dimer were available, SA ≤35 g/L was inversely associated with hs-CRP and D-dimer. During the follow-up, a total of 61 patients experienced PVT. A Kaplan Meier survival analysis showed SA ≤35 g/L was associated to increased risk of PVT compared to SA >35 g/L (P =.005). A multivariate Cox proportional hazards regression analysis showed that male sex, lower platelet count, and SA ≤35 g/L remained associated to PVT after adjusting for confounding factors. Conclusion: Cirrhotic patients with SA ≤35 g/L are at higher risk of experiencing PVT compared to those with SA >35 g/L and could be considered as potential candidates to anticoagulant prophylaxis for PVT prevention

Asymptomatic and symptomatic deep venous thrombosis in hospitalized acutely ill medical patients: risk factors and therapeutic implications

Background Acutely ill medical patients experience deep venous thrombosis (DVT) during the hospitalization, however the time course of DVT is still unclear. Objectives To evaluate risk factors in acutely ill hospitalized medical patients for proximal asymptomatic DVT (ADVT) and symptomatic DVT (SDVT) at admission and discharge. Patients/Methods In this prospective observational study, consecutive acutely ill medical patients (hospitalized mainly for acute medical disease as infections, neoplasm, anemia, heart failure) underwent compression ultrasonography (CUS) of proximal lower limb veins within 48 h from admission and at discharge to diagnose ADVT and SDVT. Covid-19 patients, anticoagulant therapy, surgical procedures, acute SDVT, and acute pulmonary embolism, were exclusion criteria. Biographical characteristics at hospitalization, D-Dimer (assessed by ELISA)) and DD-improve score. Results Of 2,100 patients (1002 females, 998 males, age 71 +/- 16 years) 58 (2.7%) had proximal ADVT at admission. Logistic regression analysis showed that age, and active cancer were independently associated with ADVT at admission. The median length of hospitalization was 10 days [interquartile range: 6-15]. During the hospital stay, 6 patients (0.3%) with a negative CUS at admission experienced DVT (2 SDVT and 4 ADVT). In the subgroup of patients (n = 1118), in whom D-dimer was measured at admission, D-Dimer and IMPROVE-DD score were associated with ADVT at admission (n = 37) and with all DVT (n = 42) at discharge. ROC curve defined an IMPROVE-DD score of 2.5 as the optimal cut-off for discriminating patients with and without thrombotic events. Conclusions We provide evidence of early development of ADVT in unselected acutely ill medical patients suggesting the need of investigating patients by CUS immediately after hospital admission (within 48 h). Advanced age, active cancer, known thrombophilia and increased IMPROVE-DD score may identify patients at risk. The benefit of anticoagulation needs to be investigated in patients with these specific risk factors and negative CUS at admission