Aging-Related Decline of Glutathione Peroxidase 3 and Risk of Cardiovascular Events in Patients With Atrial Fibrillation

BACKGROUND: Experimental studies demonstrated that glutathione peroxidase 3 (GPx3), an antioxidant enzyme that catabolizes hydrogen peroxide, protects against thrombosis. Little is known about its role in cardiovascular disease. METHODS AND RESULTS: A prospective cohort study was conducted in 909 atrial fibrillation patients. Serum activities of GPx3, superoxide dismutase (SOD), and catalase were measured at baseline to assess the risk of cardiovascular events during a mean follow-up of 43.4 months (3291 person-years). Serum Nox2 and urinary excretion of 11-deydro-thromboxane B2 were also measured. During follow-up 160 cardiovascular events occurred (4.9%/year). Significantly lower values of GPx3 (P<0.001) and SOD (P=0.037) were detected in patients with, compared to those without, cardiovascular events. A lower survival rate was observed in patients with GPx3 (P<0.001) and SOD (P=0.010) activities below the median, as compared to those above. In a fully adjusted Cox regression model, GPx3 was the only antioxidant enzyme predictor of cardiovascular events (hazard ratio 0.647, 95% confidence interval 0.524-0.798, P<0.001). GPx3 was inversely associated with urinary 11-dehydro-thromboxane B2 (B -0.337, P<0.001) and serum Nox2 (B: -0.423, P<0.001). GPx3 activity progressively decreased with decades of age (P<0.001), with a progressive reduction in people aged ≥70 years. CONCLUSIONS: This study provides evidence that a low antioxidant status, as depicted by reduced levels of GPx3, increases the risk of cardiovascular events in patients with atrial fibrillation. The age-related decline of GPx3 may represent a mechanism for the enhanced cardiovascular risk in the elderly population

Effects of Smoking on Oxidative Stress and Vascular Function

Tobacco smoking is the single most preventable risk factor related to the development of cardiovascular disease. It was demonstrated that tobacco smoke contains a thousand compounds potentially harmful to human health. As tobacco use declined over time, electronic cigarettes were introduced as an alternative. E-cigarettes are a modern and technological surrogate of traditional cigarettes and use heat to convert a nicotine solution or a flavored nicotine-free solution into vapor. Even though all the ingredients contained in the liquid of E-cigarettes are approved as food additives, the harmlessness of these electronic devices is still not fully proven in humans. The general mechanisms by which smoking results in cardiovascular events include the development of atherosclerotic changes with a hypercoagulable state and an increased risk of thrombosis. Endothelial dysfunction has been recognized as a hallmark of preclinical systemic atherosclerosis and as a useful marker to stratify the risk of cardiovascular disease. Based on these considerations, in this chapter, we (1) discussed the role of endothelial dysfunction and its contributing factors, such as oxidative stress and inflammation, in the development of cardiovascular diseases and (2) reported the studies which investigated the effect of tobacco and electronic smoking on the biomarkers of endothelial dysfunction, oxidative stress, and inflammation

Is there an interplay between adherence to mediterranean diet, antioxidant status, and vascular disease in atrial fibrillation patients?

Mediterranean Diet (Med-Diet) is associated with reduced incidence of vascular events (VEs) in atrial fibrillation (AF), but the mechanism accounting for its beneficial effect is only partially known. We hypothesized that Med-Diet may reduce VEs by improving antioxidant status, as assessed by glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). We performed a prospective cohort study investigating the relationship between adherence to Med-Diet, serum baseline GPx3 and SOD activities, and the occurrence of VEs in 690 AF patients. GPx3 activity was directly associated with Med-Diet score (B = 0.192, p &lt; 0.001) and inversely with age (B = −0.124, p = 0.001), after adjustment for potential confounders; Med-Diet weakly affected SOD levels. During a mean follow-up of 46.1 ± 28.2 months, 89 VEs were recorded; patients with VEs had lower GPx3 levels compared with those without VEs (p = 0.002); and no differences regarding SOD activity were found. Multivariable Cox regression analysis showed that age (Hazard ratio [HR]:1.065, p &lt; 0.001), logGPx3 (above median, HR: 0.629, p &lt; 0.05), and Med-Diet score (HR: 0.547, p &lt; 0.05) predicted VEs. Med-Diet favorably modulates antioxidant activity of GPx3 in AF, resulting in reduced VEs rate. We hypothesize that the modulation of GPx3 levels by Med-Diet could represent an additional nutritional strategy to prevent VEs in AF patients

Gut-Derived Serum Lipopolysaccharide is Associated With Enhanced Risk of Major Adverse Cardiovascular Events in Atrial Fibrillation: Effect of Adherence to Mediterranean Diet

Gut microbiota is emerging as a novel risk factor for atherothrombosis, but the predictive role of gut-derived lipopolysaccharide (LPS) is unknown. We analyzed (1) the association between LPS and major adverse cardiovascular events (MACE) in atrial fibrillation (AF) and (2) its relationship with adherence to a Mediterranean diet (Med-diet)

Extra virgin olive oil and cardiovascular diseases: benefits for human health

The cardioprotective properties of Mediterranean Diet were demonstrated for the first time from the Seven Country Study. In the last few decades, numerous epidemiological studies, as well as intervention trial, confirmed this observation, pointing out the close relationship between the Mediterranean diet and cardiovascular diseases. In this context, extra virgin olive oil (EVOO), the most representative component of this diet, seems to be relevant in lowering the incidence of cardiovascular events, including myocardial infarction and stroke. From a chemical point of view, 98-99% of the total weight of EVOO is represented by fatty acids, especially monounsaturated fatty acids such as oleic acid. Tocopherols, polyphenols and other minor constituents represent the remaining 1-2%. All these components may potentially contribute to "health maintenance" with their beneficial effects by EVOOO

Lipopolysaccharide as trigger of platelet aggregation via eicosanoid over-production

The effect of lipopolysaccharide (LPS) on platelet aggregation is still controversial. We performed in vitro and ex vivo studies in controls and in patients with community-acquired pneumonia (CAP) to assess the effect of LPS on platelet activation (PA). LPS (15-100 pg/ml) significantly increased PA only if combined with sub-threshold concentrations (STC) of collagen or ADP; this effect was associated with increased platelet H2O2 production, Nox2 activation, PLA2 phosphorylation, thromboxane (Tx)A2 and 8-iso-PGF2α-III, and was inhibited by aspirin, TxA2 receptor antagonist or by Toll-like receptor 4 blocking peptide (TLR4bp). Analysis of up-stream signalling potentially responsible for Nox2 and PLA2 activation demonstrated that LPS-mediated PA was associated with phosphorylation of AKT, p38 and p47phox translocation. In 10 consecutive CAP patients serum endotoxins were significantly higher compared to 10 controls (145 [115-187] vs 18 [6-21] pg/ml; p<0.01). Ex vivo study showed that agonist-stimulated platelets were associated with enhanced PA (p<0.01), Toll-like receptor 4 (TLR4) expression (p<0.05), thromboxane (Tx)A2 (p<0.01) and 8-iso-PGF2α-III (p<0.01) production in CAP patients compared to controls. The study provides evidence that LPS amplifies the platelet response to common agonists via TLR4-mediated eicosanoid production and suggests LPS as a potential trigger for PA in CAP

Is there an interplay between adherence to mediterranean diet, antioxidant status, and vascular disease in atrial fibrillation patients?

Mediterranean Diet (Med-Diet) is associated with reduced incidence of vascular events (VEs) in atrial fibrillation (AF), but the mechanism accounting for its beneficial effect is only partially known. We hypothesized that Med-Diet may reduce VEs by improving antioxidant status, as assessed by glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). We performed a prospective cohort study investigating the relationship between adherence to Med-Diet, serum baseline GPx3 and SOD activities, and the occurrence of VEs in 690 AF patients. GPx3 activity was directly associated with Med-Diet score (B = 0.192, p &lt; 0.001) and inversely with age (B = −0.124, p = 0.001), after adjustment for potential confounders; Med-Diet weakly affected SOD levels. During a mean follow-up of 46.1 ± 28.2 months, 89 VEs were recorded; patients with VEs had lower GPx3 levels compared with those without VEs (p = 0.002); and no differences regarding SOD activity were found. Multivariable Cox regression analysis showed that age (Hazard ratio [HR]:1.065, p &lt; 0.001), logGPx3 (above median, HR: 0.629, p &lt; 0.05), and Med-Diet score (HR: 0.547, p &lt; 0.05) predicted VEs. Med-Diet favorably modulates antioxidant activity of GPx3 in AF, resulting in reduced VEs rate. We hypothesize that the modulation of GPx3 levels by Med-Diet could represent an additional nutritional strategy to prevent VEs in AF patients

Extra virgin olive oil use is associated with improved post-prandial blood glucose and LDL cholesterol in healthy subjects

Extra virgin olive oil (EVOO) is a key component of the Mediterranean diet and seems to account for the protective effect against cardiovascular disease. However, the underlying mechanism is still elusive

Digoxin and platelet activation in patients with atrial fibrillation: In vivo and in vitro study

Background-Digoxin use was shown to be associated with an increased risk of cardiovascular events in atrial fibrillation (AF). We hypothesized that digoxin may affect cardiovascular risk by increasing platelet activation. Methods and Results-Post hoc analysis of a prospective study of anticoagulated patients with AF. Patients were divided into 2 groups balanced for age, sex, and cardiovascular risk factors: digoxin users (n=132) and nonusers (n=388). Urinary excretion of 11‐dehydro‐thromboxane B2 (TxB2), a marker of platelet activation, and serum digoxin concentration (SDC) were measured. In vitro experiments were performed on platelets from healthy subjects and AF patients, which were incubated with scalar doses of digoxin (0.6-2.4 ng/mL) with or without prestimulation with a sub‐threshold of collagen. Median 11‐dehydro‐TxB2 was 105.0 (interquartile range, 60.0-190.0) ng/mg creatinine, and median SDC was 0.65 (interquartile range, 0.40-1.00) ng/mL. Urinary 11‐dehydro‐TxB2 and SDC were correlated (rs=0.350, P<0.001). Patients in the upper tertile of SDC showed higher 11‐dehydro‐TxB2 compared with non-digoxin users (P=0.019). In vitro study showed an increased basal platelet activation in patients with AF compared with healthy subjects. Digoxin (2.4 ng/mL) induced calcium mobilization, PAC‐1 (procaspase‐activating compound 1) and platelet aggregation in AF patients but not in healthy subjects. After pretreatment with a sub‐threshold of collagen, digoxin dose‐dependent induced calcium mobilization, arachidonic acid release, TxB2 biosynthesis, PAC‐1 and soluble platelet selectin expression, and platelet aggregation, which were inhibited by antibody against digoxin. Conclusions-We found a significant in vivo correlation between SDC and platelet activation. Supratherapeutic SDC increased in vitro platelet aggregation via calcium‐related phospholipase A2 phosphorylation. Our findings may have clinical implications for AF patients treated with digoxin