[Show abstract][Hide abstract] ABSTRACT: NOX-2, the catalytic subunit of NADPH oxidase, has a key role in the formation of reactive oxidant species and is implicated in impairing flow-mediated dilation (FMD). Dark chocolate exerts artery dilatation via down-regulating NOX2-mediated oxidative stress. The aim of this study was to investigate whether dark chocolate improves walking autonomy in peripheral artery disease (PAD) patients via an oxidative stress-mediated mechanism.
Journal of the American Heart Association. 01/2014; 3(4).
[Show abstract][Hide abstract] ABSTRACT: Background:Studies conducted in pre-pubertal period showed that biomarkers of oxidative stress decreased with increasing age in normocholesterolemic children (NC) and, conversely, they are persistently high in hypercholesterolemic children (HC). Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is the most important cellular source of reactive oxygen species. No data have been reported concerning the behavior of age-related oxidative stress generated by NOX-2, the catalytic subunit of NADPH oxidase, in children.Methods:We performed a cross-sectional study comparing oxidized-LDL (ox-LDL), as marker of oxidative stress, and NOX2 activity, as assessed by blood levels of soluble NOX2-derived peptide (sNOX2-dp), in a population of 250 children, including 125 NC and 125 HC.Results:HC had higher sNOX2-dp (25.8±16.1 pg/ml) and ox-LDL (23.6±14.4 U/l) levels compared to NC (15.4±10.1 and 11.6±6.4 pg/ml, respectively; p<0.001). Multiple linear regression analysis showed that ox-LDL and total cholesterol were the only independent predictive variables associated with sNOX2-dp. In NC, ox-LDL and sNOX2-dp significantly decreased from first to second quintile of age. In HC oxidized-LDL and sNOX2-dp levels did not show significant differences among quintiles of age.Conclusion:The study suggests that NOX2 contributes to generating ox-LDL during the early phase of life in NC and to the persistent high oxidative stress in the pre-pubertal period of HC.Pediatric Research (2013); doi:10.1038/pr.2013.55.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: NADPH oxidase, one of the most important enzymes producing reactive oxidant species, is suggested to play a role in experimental atherosclerosis, but its role in human atherosclerosis is still unclear. We hypothesized that a reduced activity of NADPH oxidase might be linked to a reduced atherosclerotic burden. METHODS AND RESULTS: Thirty-one women carriers of hereditary deficiency of NOX2, the catalytic subunit of NADPH oxidase, were matched for sex and age with 31 controls and 31 obese women. Flow-mediated dilation and intima-media thickness, 2 surrogate markers of atherosclerosis, serum activity of NOX2, urinary isoprostanes, serum levels of nitrite/nitrate, and platelet production of isoprostanes and nitrite/nitrate were determined.Compared with controls (5.7±3.0% and 0.60±0.11 mm), carriers of NOX2 deficiency had higher flow-mediated dilation (9.2±5.0%; P<0.001) and lower intima-media thickness (0.50±0.11 mm; P=0.002), whereas obese women had lower flow-mediated dilation (3.2±2.1%; P=0.007) and higher intima-media thickness (0.71±0.15 mm; P<0.001). Compared with controls, carriers of NOX2 deficiency had lower urinary isoprostanes (132.6±87.3 versus 82.3±46.0 pg/mg creatinine; P=0.007) and serum NOX2 activity (24.9±19.3 versus 12.8±11.9 pg/mL; P=0.004) and higher serum nitrite/nitrate (23.8±7.6 versus 30.5±6.3 µmol/L; P<0.001), whereas obese women had higher urinary isoprostanes (132.6±87.3 versus 182.2±84.6 pg/mg creatinine; P=0.008) and serum NOX2 activity (24.9±19.3 versus 36.1±18.6 pg/mL; P=0.008) and lower serum nitrite/nitrate (23.8±7.6 versus 12.6±4.2 µmol/L; P<0.001). Flow-mediated dilation correlated with intima-media thickness (r=-0.433; P<0.001), serum NOX2 activity (r=-325; P<0.001), and urinary isoprostanes (r=-0.314; P=0.002). Ex vivo study showed that, compared with controls, platelets from carriers of NOX2 deficiency had lower isoprostanes (P<0.001) and higher nitrite/nitrate (P<0.001), whereas platelets from obese women had higher isoprostanes (P<0.001) and lower nitrite/nitrate (P=0.013). CONCLUSIONS: The study shows reduced atherosclerotic burden in carriers of NOX2 deficiency, suggesting that oxidative stress generated by this enzymatic pathway is implicated in human atherosclerosis.
Arteriosclerosis Thrombosis and Vascular Biology 01/2013; · 6.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: To analyze the interplay among oxidative stress, NOX2, the catalytic core of nicotinamide-adenine dinucleotide phosphate oxidase, and endothelial dysfunction in children with obesity and/or hypercholesterolemia. STUDY DESIGN: We performed a cross-sectional study comparing flow-mediated arterial dilation (FMD), oxidized low-density lipoprotein, and urinary excretion of isoprostanes (8-iso-PGF2α), as markers of oxidative stress, and NOX2 activity, as assessed by blood levels of soluble NOX2-dp (sNOX2-dp), in a population of 100 children, matched for age and sex, including 40 healthy subjects (HS), 20 children with hypercholesterolemia (HC), 20 obese children (OC), and 20 children with coexistence of hypercholesterolemia and obesity (HOC). RESULTS: HOC had higher sNOX2-dp and oxidized low-density lipoprotein levels compared with HS, HC, and OC. HC, OC, and HOC had lower FMD values compared with HS. Urinary 8-iso-PGF2α excretion was higher in HOC compared with HS. FMD was inversely correlated with sNOX2-dp levels (r = -0.483; P < .001) and with the number of cardiovascular risk factors (r = -0.617; P < .001). Multiple linear regression analysis showed that the number of cardiovascular risk factors was the only independent predictive variable associated with FMD (β: -0.585; P < .001; R(2) = 35%) and sNOX2-dp (β: 0.587; P < .001; R(2) = 34%). CONCLUSION: The study suggests that NOX2-generating oxidative stress may have a pathogenic role in the functional changes of the arterial wall occurring in HOC.
The Journal of pediatrics 06/2012; · 4.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oxidative stress is suggested to play a role in favoring the occurrence of atrial fibrillation (AF). We analyzed whether vitamin E, a known antioxidant, or markers of oxidative stress are associated with AF recurrence in patients undergoing electric cardioversion.
A total of 144 patients (83 men; mean age, 71.1±5.4 years) underwent successful biphasic electric cardioversion of nonvalvular persistent AF. At baseline, urinary 8-isoprostaglandin F2α and serum soluble NOX2-derived peptide (sNOX2-dp), high-sensitivity C-reactive protein (hs-CRP), and vitamin E levels were measured in each patient. All patients underwent 3 months of clinical follow-up, including an office visit with ECG every week or in cases of symptom recurrence. During the follow-up, 94 patients maintained sinus rhythm, whereas 50 experienced AF recurrence. In unadjusted analysis, left atrial diameter and levels of urinary isoprostanes and serum sNOX2-dp and hs-CRP were significantly higher and serum vitamin E lower in patients with AF recurrence. In multivariable Cox analysis, serum vitamin E (hazard ratio, 0.734; 95% CI, 0.605-0.891; P<0.001) and, to a lesser extent, hs-CRP (P=0.047) remained significantly associated with AF recurrence. Urinary isoprostanes and serum sNOX2-dp levels were inversely correlated with serum vitamin E level (r=-0.626, P<0.001, and r=-0.460, P<0.001, respectively).
The study shows that low serum vitamin E levels are associated with AF recurrence in patients who underwent cardioversion. Because vitamin E inversely correlated with oxidative stress, the findings reinforce the hypothesis of an interplay between oxidative stress and AF.
Circulation Arrhythmia and Electrophysiology 02/2012; 5(2):327-33. · 5.95 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dark chocolate is reported to decrease platelet activation but the underlying mechanism is still undefined. Dark chocolate is rich in polyphenols that could exert an antiplatelet action via inhibition of oxidative stress. The aim of the present study was to assess if dark chocolate inhibits platelet reactive oxidant species (ROS) formation and platelet activation.
Twenty healthy subjects (HS) and 20 smokers were randomly allocated to receive 40 g of dark (cocoa > 85%) or milk chocolate (cocoa < 35%) in a cross-over, single-blind study. There was an interval of 7 days between the two phases of the study. At baseline and 2 h after chocolate ingestion, platelet recruitment (PR), platelet ROS, platelet isoprostane 8-ISO-prostaglandin F2α (8-iso-PGF2α), Thromboxane (TxA2) and platelet activation of NOX2, the catalytic sub-unit of NADPH oxidase, and serum epicatechin were measured.
Compared with HS, smokers showed enhanced PR, platelet formation of ROS and eicosanoids and NOX2 activation. After dark chocolate, platelet ROS (-48%, P < 0.001), 8-iso-PGF2α (-10%, P < 0.001) and NOX2 activation (-22%, P < 0.001) significantly decreased; dark chocolate did not affect platelet variables in HS. No effect of milk chocolate was detected in both groups. Serum epicatechin increased after dark chocolate in HS (from 0.454 ± 0.3 nm to 118.3 ± 53.7 nm) and smokers (from 0.5 ± 0.28 nm to 120.9 ± 54.2 nm). Platelet incubation with 0.1-10 μm catechin significantly reduced PR, platelet 8-iso-PGF2α and ROS formation and NOX2 activation only in platelets from smokers.
Dark chocolate inhibits platelet function by lowering oxidative stress only in smokers; this effect seems to be dependent on its polyphenolic content.
Journal of Thrombosis and Haemostasis 11/2011; 10(1):125-32. · 6.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cocoa seems to exert artery dilatation via oxidative stress inhibition but the mechanism is still unclear.
To investigate whether in smokers, dark chocolate elicits artery dilatation via down-regulation of NOX2, the catalytic core of NADPH oxidase.
Flow-mediated dilatation (FMD), oxidative stress (as assessed by urinary isoprostanes excretion), nitric oxide generation (as assessed by serum levels of nitrite/nitrate (NOx)), NOX2 activity (as assessed by blood levels of soluble NOX2 derived peptide (sNOX2-dp)) and serum epicatechin were studied in 20 smokers and 20 healthy subjects (HS) in a crossover, single-blind study. Patients were randomly allocated to 40 g dark chocolate (>85% cocoa) or 40 g of milk chocolate (≤35% cocoa). FMD, urinary isoprostanes, NOx and sNOX2-dp were assessed at baseline and 2 h after chocolate ingestion.
Smokers had lower FMD and NOx and higher sNOX2-dp compared to HS. After dark chocolate intake, urinary isoprostanes and sNOX2-dp significantly decreased and FMD and NOx significantly increased in smokers but not in HS. No changes of the above variables were observed after milk chocolate intake. Multiple linear regression analysis showed that in smokers the only independent predictive variable associated with a change in FMD was a change in sNOX2-dp. Serum epicatechin increased in either group only after dark chocolate intake, reaching values higher than 0.1 μM. Platelets from smokers (n=5), but not from HS (n=5), showed lower p47(phox) translocation to platelet membrane and higher NOx when incubated with 0.1-10 μM epicatechin.
Results suggest that in smokers, cocoa enhances artery dilatation by lowering of NOX2 activation.
[Show abstract][Hide abstract] ABSTRACT: Studies conducted in healthy children showed that biomarkers of oxidative stress decreased with increasing age from 1 to 11 years. No data have been reported concerning the behavior of age-related oxidative stress in hypercholesterolemic children.
Aim of this study was to test if children with hypercholesterolemia have prolonged exposure to enhanced oxidative stress and to study the underlying mechanism.
We performed a cross-sectional study comparing 8-hydroxy-2'deoxyguanosine, oxidized-LDL and myeloperoxidase plasma levels in 95 normocholesterolemic and 95 hypercholesterolemic children.
Compared to normocholesterolemic children, those with hypercholesterolemia had higher 8-hydroxy-2'deoxyguanosine, oxidized-LDL and myeloperoxidase plasma levels. A correlation analysis of the overall population showed that total cholesterol was directly correlated with 8-hydroxy-2'deoxyguanosine, oxidized-LDL and myeloperoxidase. Stepwise linear regression showed that only total cholesterol, 8-hydroxy-2'deoxyguanosine and myeloperoxidase levels predicted oxidized-LDL plasma levels. In normocholesterolemic children oxidized-LDL and myeloperoxidase plasma levels significantly decreased from first (1-5 years) to second (6-9 years) quartile of age. In hypercholesterolemic children 8-hydroxy-2'deoxyguanosine, oxidized-LDL and myeloperoxidase plasma levels did not show significant differences among quartiles of age.
This study shows that an early and persistent oxidative stress is detected in hypercholesterolemic children and that myeloperoxidase up-regulation might play a role.
[Show abstract][Hide abstract] ABSTRACT: Endothelial dysfunction and intima-media thickness are precocious manifestations of hypercholesterolemia, but the mechanism is unclear.
The aim of the study was to analyze the interplay among endothelial dysfunction, intima-media thickness, and oxidative stress in children with hypercholesterolemia.
We performed a cross-sectional study comparing flow-mediated dilation, intima-media thickness, lipid profile, urinary isoprostanes as markers of oxidative stress, and platelet expression of gp91(phox), the catalytic unit of nicotinamide-adenine dinucleotide phosphate oxidase, in a population of 50 children with hypercholesterolemia (mean age +/- SD: 10.0 +/- 3.7 years) and 50 children without hypercholesterolemia (mean age: 9.2 +/- 3.5 years). Four children with hereditary deficiency of gp91(phox) were studied also.
Children with hypercholesterolemia had reduced flow-mediated dilation (mean +/- SD: 6.2 +/- 2.4 vs 9.2 +/- 2.5%) and enhanced intima-media thickness (0.45 +/- 0.07 vs 0.40 +/- 0.06 mm), urinary isoprostanes (86.9 +/- 51.6 vs 45.9 +/- 25.6 pg/mg creatinine), and gp91(phox) platelet expression (4.4 +/- 3.8 vs 2.0 +/- 1.7 mean fluorescence) compared with control subjects. At bivariate analysis, flow-mediated dilation was correlated with low-density lipoprotein cholesterol, intima-media thickness, urinary isoprostanes, and platelet gp91(phox). Stepwise multiple linear regression analysis showed that, in children with hypercholesterolemia, flow-mediated dilation and intima-media thickness were significantly associated with low-density lipoprotein cholesterol and urinary isoprostanes; also, gp91(phox) platelet expression was an independent predictor of urinary isoprostanes. Children with gp91(phox) hereditary deficiency showed downregulation of platelet gp91(phox) and reduced urinary excretion of isoprostanes.
The study suggests that gp91(phox)-mediated oxidative stress may have a pathogenic role in the anatomic and functional changes of the arterial wall occurring in children with premature atherosclerosis.