177 research outputs found
Garnet characterization of plutonic rocks from the Pisuerga-CarriĂłn Unit (Cantabrian Zone)
Ministerio de EducaciĂłn y Ciencia; PB-94-1338Ministerio de EducaciĂłn y Ciencia; PB-98-153
NADPH OxidaseâDependent Superoxide Production Is Associated With Carotid Intima-Media Thickness in Subjects Free of Clinical Atherosclerotic Disease
ObjectiveâOxidative stress plays a critical role in the pathogenesis of atherosclerosis. The NADPH oxidase constitutes the
main source of superoxide in phagocytic and vascular cells. This study aimed to investigate the levels of NADPH
oxidaseâmediated superoxide production in phagocytic cells and the association between phagocytic superoxide
production and carotid intima-media thickness (IMT), a surrogate marker of asymptomatic atherosclerosis.
Methods and ResultsâNADPH oxidaseâmediated superoxide production was determined by a chemiluminescence assay
using lucigenin and associated with IMT for 184 asymptomatic subjects free of overt clinical atherosclerotic disease.
Compared with individuals in the lowest tertile of superoxide production, those in the upper tertile ( 20 counts/sec)
showed significantly higher IMT (P 0.05). In correlation analysis, a positive relationship was found between
superoxide production and carotid IMT. Superoxide production also correlated positively (P 0.05) with body mass
index (BMI). In multivariate analysis, the association of superoxide production with carotid IMT remained significant
after adjustment for age, sex, systolic blood pressure, BMI, triglycerides, glucose, and smoking.
ConclusionsâIn a population sample of adults without clinically overt atherosclerotic disease, increased NADPH oxidase
activity was associated with enhanced carotid IMT, suggesting a relationship between phagocytic NADPH oxidaseâ
mediated oxidative stress and the development of atherosclerosis
Increased phagocytic nicotinamide adenine dinucleotide phosphate oxidaseâdependent superoxide production in patients with early chronic kidney disease
Background. Oxidative stress has been implicated in the
pathogenesis of atherosclerosis that develops in patients with
advanced chronic kidney disease (CKD). This study was
designed to investigate whether a relationship exists between
phagocytic nicotinamide adenine dinucleotide phosphate
(NADPH) oxidaseâdependent superoxide anion (âąO2
â) production
and subclinical atherosclerosis in patients with early
CKD.
Methods. Superoxide production was assayed by chemiluminescence
under baseline and stimulated conditions on mononuclear
cells obtained from asymptomatic patients with stage 1
to 2 CKD (N = 22) and healthy controls (N = 21). Ultrasonographic
determination of carotid intima-media thickness (IMT)
was used to assess the presence of atherosclerosis.
Results. Although there were no differences in baseline âąO2
â
production between controls and patients, the âąO2
â production
in phorbol myristate acetateâstimulated mononuclear cells was
increased (P < 0.05) in patients compared with controls. The
phorbol myristate acetateâinduced âąO2
â production was completely
abolished by apocynin, a specific inhibitor of NADPH
oxidase. A direct correlation (r = 0.441, P < 0.05) was found
between plasma insulin levels and NADPH oxidaseâmediated
âąO2
â production in patients. Carotid IMT was higher (P <
0.005) in patients than in controls. CarotidIMTvalues above the
upper normal limit in controls were found in 70% and 40% of
patients with increased or normal NADPH oxidaseâmediated
âąO2
â production, respectively.
Conclusion. Generation of âąO2
â that is mainly dependent on
NADPH oxidase is abnormally enhanced in patients with early
CKD. It is suggested that this alteration could be related to the
development of subclinical atherosclerosis in these patients
Functional Effect of the p22phox -930A/G Polymorphism on p22phox Expression and NADPH Oxidase Activity in Hypertension
Oxidative stress induced by superoxide is implicated in hypertension. NADPH oxidase is the main source of
superoxide in phagocytic and vascular cells, and the p22phox subunit is involved in NADPH oxidase activation. Recently
we reported an association of 930A/G polymorphism in the human p22phox gene promoter with hypertension. This study
was designed to investigate the functional role of this polymorphism in hypertension. We thus investigated the
relationships between the 930A/G polymorphism and p22phox expression and NADPH oxidaseâmediated superoxide
production in phagocytic cells from 70 patients with essential hypertension and 70 normotensive controls. Genotyping
of the polymorphism was performed by restriction fragment length polymorphism. NADPH oxidase activity was
determined by chemiluminescence assays, and p22phox mRNA and protein expression was measured by Northern and
Western blotting, respectively. Compared with hypertensive subjects with the AA/AG genotype, hypertensive subjects
with the GG genotype exhibited increased (P 0.05) phagocytic p22phox mRNA (1.26 0.06 arbitrary unit [AU] versus
0.99 0.03 AU) and protein levels (0.58 0.05 AU versus 0.34 0.04 AU) and enhanced NADPH oxidase activity
(1998 181 counts/s versus 1322 112 counts/s). No differences in these parameters were observed among genotypes
in normotensive cells. Transfection experiments on vascular smooth muscle cells showed that the A-to-G substitution
of this polymorphism produced an increased reporter gene expression in hypertensive cells. Nitric oxide production, as
assessed by measurement of serum nitric oxide metabolites, was lower in GG hypertensive subjects than in AA/AG
hypertensive subjects. In conclusion, these results suggest that hypertensive subjects carrying the GG genotype of the
p22phox 930A/G polymorphism are highly exposed to NADPH oxidase-mediated oxidative stress
Preliminary characterisation of the promoter of the human p22phox gene: identification of a new polymorphism associated with hypertension
The p22(phox) subunit is an essential protein in the activation of NAD(P)H oxidase. Here we report the preliminary characterisation of the human p22(phox) gene promoter. The p22(phox) promoter contains TATA and CCAC boxes and Sp1, gamma-interferon and nuclear factor kappaB sites. We screened for mutations in the p22(phox) promoter and identified a new polymorphism, localised at position -930 from the ATG codon, which was associated with hypertension. Mutagenesis experiments showed that the G allele had higher promoter activity than the A allele. These results suggest that the -930(A/G) polymorphism in the p22(phox) promoter may be a novel genetic marker associated with hypertension
Association of increased phagocytic NADPH oxidasedependent superoxide production with diminished nitric oxide generation in essential hypertension
Objective: Oxidative stress has been implicated in the pathogenesis of hypertension and its complications through alterations in nitric oxide (NO) metabolism. This study was designed to investigate whether a relationship exists between phagocytic nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent superoxide anion (âąO2-) production and NO generation in patients with essential hypertension.
Methods: Superoxide production was assayed by chemiluminescence under baseline and stimulated conditions on mononuclear cells obtained from hypertensives (n = 51) and normotensives (n = 43). NO production was evaluated by determining serum NO metabolites, nitrate plus nitrite (NOx).
Results: Although there were no differences in baseline âąO2- production between normotensives and hypertensives, the âąO2- production in phorbol myristate acetate (PMA)-stimulated mononuclear cells was increased (P < 0.05) in hypertensives compared with normotensives. The PMA-induced âąO2- production was completely abolished by apocynin, a specific inhibitor of NADPH oxidase. Moreover, stimulation of âąO2- production by angiotensin II and endothelin-1 was higher (P < 0.05) in cells from hypertensives than in cells from normotensives. In addition, diminished (P < 0.001) serum NOx was detected in hypertensives compared with normotensives. Interestingly, an inverse correlation (r = 0.493, P < 0.01) was found between âąO2- production and NOx in hypertensives.
Conclusions: Generation of âąO2- mainly dependent on NADPH oxidase is abnormally enhanced in stimulated mononuclear cells from hypertensives. It is suggested that this alteration could be involved in the diminished NO production observed in these patients
The A640G CYBA polymorphism associates with subclinical atherosclerosis in diabetes
Oxidative stress is implicated in diabetes. The NADPH oxidases are the main source of superoxide in phagocytic and vascular cells, and p22phox is a key subunit. Genetic variants of CYBA, the human p22phox gene, associate with cardiovascular disease. We investigated the association of the A640G polymorphism with diabetes and its impact on phagocytic NADPH oxidase-dependent superoxide production and subclinical atherosclerosis. We studied 1212 subjects in which clinical parameters including carotid intima-media thickness (cIMT) were assessed. The A640G polymorphism was genotyped by TaqMan probes. In 496 subjects, the NADPH oxidase-dependent superoxide production in peripheral blood mononuclear cells was assessed by chemiluminescence. The GG genotype prevalence was significantly higher in type 2 diabetic patients than in non-diabetic subjects. Peripheral blood mononuclear cells from diabetic GG patients presented higher NADPH oxidase-dependent superoxide production than those of diabetic AA/AG patients. Within the diabetic group, GG patients presented higher cIMT levels than AA/AG patients. The A640G CYBA polymorphism may be a marker of oxidative stress risk and may be indicative of subclinical atherosclerosis in type 2 diabetes
The Inflammasome Drives GSDMD-Independent Secondary Pyroptosis and IL-1 Release in the Absence of Caspase-1 Protease Activity.
Inflammasomes activate the protease caspase-1, which cleaves interleukin-1ÎČ and interleukin-18 to generate the mature cytokines and controls their secretion and a form of inflammatory cell death called pyroptosis. By generating mice expressing enzymatically inactive caspase-1 <sup>C284A</sup> , we provide genetic evidence that caspase-1 protease activity is required for canonical IL-1 secretion, pyroptosis, and inflammasome-mediated immunity. In caspase-1-deficient cells, caspase-8 can be activated at the inflammasome. Using mice either lacking the pyroptosis effector gasdermin D (GSDMD) or expressing caspase-1 <sup>C284A</sup> , we found that GSDMD-dependent pyroptosis prevented caspase-8 activation at the inflammasome. In the absence of GSDMD-dependent pyroptosis, the inflammasome engaged a delayed, alternative form of lytic cell death that was accompanied by the release of large amounts of mature IL-1 and contributed to host protection. Features of this cell death modality distinguished it from apoptosis, suggesting it may represent a distinct form of pro-inflammatory regulated necrosis
From modular to centralized organization of synchronization in functional areas of the cat cerebral cortex
Recent studies have pointed out the importance of transient synchronization
between widely distributed neural assemblies to understand conscious
perception. These neural assemblies form intricate networks of neurons and
synapses whose detailed map for mammals is still unknown and far from our
experimental capabilities. Only in a few cases, for example the C. elegans, we
know the complete mapping of the neuronal tissue or its mesoscopic level of
description provided by cortical areas. Here we study the process of transient
and global synchronization using a simple model of phase-coupled oscillators
assigned to cortical areas in the cerebral cat cortex. Our results highlight
the impact of the topological connectivity in the developing of
synchronization, revealing a transition in the synchronization organization
that goes from a modular decentralized coherence to a centralized synchronized
regime controlled by a few cortical areas forming a Rich-Club connectivity
pattern.Comment: 24 pages, 8 figures. Final version published in PLoS On
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