Validation of plasma fibrinogen as a marker of carotid atherosclerosis in subjects free of clinical cardiovascular disease

BACKGROUND AND OBJECTIVES: Fibrinogen has been found to be an independent risk factor for cardiovascular disease. The aim of this study was to validate the measurement of plasma fibrinogen as a marker of subclinical atherosclerosis in a series of asymptomatic subjects (n=519, median age 55.5 years, 80% men). DESIGN AND METHODS: All individuals had a complete clinical examination, lipid profile (cholesterol and its high and low density lipoprotein fractions and triglycerides), global vascular risk assessment (PROCAM), and B-mode ultrasonography of the carotid arteries to determine the intima-media thickness (IMT) and the presence of atheroma plaques. C-reactive protein (CRP), and von Willebrand factor (vWF) were also measured in all subjects as markers of inflammation/endothelial damage. RESULTS: In the univariate model, a positive relationship was found between plasma fibrinogen concentration and carotid IMT (p<0.001). Fibrinogen concentration also correlated positively with age (p<0.001), systolic blood pressure (p<0.001), smoking (p<0.05), diabetes (p<0.05), PROCAM (p<0.001), CRP and vWF (p<0.001). In the multivariate analysis, the association of fibrinogen with carotid IMT remained significant (p=0.008) after adjustment for all parameters analyzed. INTERPRETATION AND CONCLUSIONS: In a population sample of adults without clinically overt atherosclerotic disease, elevated fibrinogen levels was related to carotid IMT independently of a wide range of important confounding variables. Plasma fibrinogen may represent a systemic marker of carotid atherosclerosis

Superoxide dismutase in patients with chronic hepatitis C virus infection

It has been reported that hepatitis C virus (HCV) may cause oxidative stress in infected cells. Patients with chronic hepatitis C exhibit an increased production of tumor necrosis factor-alpha (TNF alpha), a cytokine that can produce oxidative stress by stimulating the generation of reactive oxygen species (ROS). Cell defense against ROS includes overexpression of Mn-superoxide dismutase (SOD), an inducible mitochondrial enzyme. To investigate cell defense against oxidative stress in HCV infection, we analyzed Mn-SOD mRNA in liver and in peripheral blood mononuclear cells (PBMC) from patients with chronic hepatitis C. Mn-SOD expression in PBMC was significantly increased in patients with HCV infection. Patients with sustained virological and biochemical response after therapy showed significantly lower Mn-SOD than patients with positive viremia. By contrast, Mn-SOD expression was not enhanced in the liver of patients with chronic hepatitis C. The values of Mn-SOD mRNA did not correlate with TNF alpha mRNA expression, viral load, or liver disease activity. Our results indicate that in HCV infection an induction of Mn-SOD was present in PBMC but absent in the liver, suggesting that this organ could be less protected against oxidative damage. Oxidative stress could participate in the pathogenesis of HCV infection

Relación entre las fases precoces de la enfermedad renal y el síndrome metabólico

Advanced kidney disease is a major health problem due to its association with high cardiovascular morbidity and mortality. Early recognition of advanced kidney disease is the mainstay to avoid its progression. Since metabolic syndrome and insulin resistance are risk factors for both cardiovascular and advanced kidney disease, we investigated the relationship of early kidney disease (EKD) with metabolic syndrome and insulin resistance, and their association with surrogate markers of arteriosclerosis. METHODS: We studied 1498 subjects. Insulin resistance was defined as HOMA >/=3.7 mmol (muU)/L(2) and EKD as stages 1 and 2 of the NKF-KDOQI. Carotid intima-media thickness was used as a surrogate marker of arteriosclerosis. RESULTS: The presence of one trait of metabolic syndrome was associated with an odds ratio (OR) for EKD of 2.3 (95% confidence interval [CI], 1.18-4.48) that increased to 6.72 (95% CI, 3.56-13.69) in subjects with the syndrome. All the traits of the syndrome except low level of high-density lipoproteins showed an increased OR for EKD. Increasing HOMA was also directly correlated with higher OR for EKD, being as high as 3.89 (95% CI, 1.99-7.59) for subjects in the fourth quartile. Subjects with the syndrome plus EKD showed an increased intima-media thickness compared with those without kidney disease. CONCLUSIONS: Insulin resistance and all metabolic syndrome traits except low level of high-density lipoproteins were significantly associated with an increased OR for EKD. Both metabolic syndrome and EKD were independently and additively related to the presence of surrogate markers of arteriosclerosis

Protective effect of the G-765C COX-2 polymorphism on subclinical atherosclerosis and inflammatory markers in asymptomatic subjects with cardiovascular risk factors

BACKGROUND: Cyclooxygenase (COX)-2, a key regulatory enzyme in prostanoid synthesis, plays an important role in inflammatory processes. The -765G>C COX-2 polymorphism has been associated with lower promoter activity in vitro and reduced levels of C-reactive protein (CRP) in atherosclerotic carriers of the C allele. However, its pathophysiological relevance in vivo has not been fully elucidated. METHODS AND RESULTS: We assessed the -765G>C polymorphism and COX-2 expression in 220 asymptomatic subjects free of cardiovascular disease, in relation to global vascular risk, carotid intima-media thickness (IMT), and inflammatory markers (fibrinogen, C-reactive protein [CRP], von Willebrand factor [vWF] and interleukin-6 [IL-6]). Genotype frequencies were: CC (7.7%), CG (34.5%), GG (57.7%). Among hypercholesterolemic subjects (n=140), C allele carriers had lower COX-2 expression (p<0.05), reduced carotid IMT (p<0.01) and diminished levels of inflammatory markers CRP, vWF and IL-6 (p<0.05), as compared to GG homozygous subjects. The association between carotid IMT and COX-2 polymorphism remained significant after adjusting for cardiovascular risk factors and inflammatory markers (p=0.008). CONCLUSIONS: In asymptomatic hypercholesterolemic subjects the C allele of -765G>C COX-2 polymorphism was associated with lower COX-2 expression, and reduced subclinical atherosclerosis and systemic inflammation compared with GG homozygous, thus conferring atherosclerosis protection in this cardiovascular risk population

NADPH Oxidase–Dependent Superoxide Production Is Associated With Carotid Intima-Media Thickness in Subjects Free of Clinical Atherosclerotic Disease

Objective—Oxidative 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 oxidase–mediated 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 Results—NADPH oxidase–mediated 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. Conclusions—In 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 oxidase– mediated oxidative stress and the development of atherosclerosis

Increased phagocytic nicotinamide adenine dinucleotide phosphate oxidase–dependent 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) oxidase–dependent superoxide anion (•O2 −) 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 •O2 − production between controls and patients, the •O2 − production in phorbol myristate acetate–stimulated mononuclear cells was increased (P < 0.05) in patients compared with controls. The phorbol myristate acetate–induced •O2 − 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 oxidase–mediated •O2 − 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 oxidase–mediated •O2 − production, respectively. Conclusion. Generation of •O2 − 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

Hyperhomocysteinemia in liver transplant recipients: prevalence and multivariate analysis of predisposing factors.

Liver transplant recipients have an increased risk for cardiovascular disease because of a high incidence of obesity, arterial hypertension, diabetes mellitus, and hyperlipidemia. Hyperhomocysteinemia has been found to be an important risk factor for cardiovascular disease in large studies. Fasting serum levels of homocysteine were measured in 105 liver transplant recipients, and hyperhomocysteinemia was defined as a fasting serum homocysteine level greater than 13 micromol/L. Patients with versus without hyperhomocysteinemia were compared. The possible association of hyperhomocysteinemia with age, sex, cause of liver disease, time elapsed since liver transplantation, immunosuppressive therapy, folic acid level, liver function test results, renal function, and other cardiovascular risk factors was investigated. Patients with serum homocysteine levels greater than 15 micromol/L were treated with folic acid, 10 mg/d, and serum homocysteine levels were measured again 1 to 3 months later in 10 patients. Hyperhomocysteinemia was detected in 28 patients (27%). In univariate analysis, it was associated with hepatitis C virus infection, treatment with mycophenolate mofetil, and greater serum levels of alkaline phosphatase, gamma-glutamyl transpeptidase, urea, and creatinine. In multivariate analysis, only greater serum levels of creatinine (P =.006) were associated with hyperhomocysteinemia. Treatment with folic acid resulted in a decrease in fasting serum homocysteine levels in 9 of the 10 patients tested (P =.01). Hyperhomocystinemia, associated with renal dysfunction, is a frequent finding in liver transplant recipients. Treatment with folic acid may reduce fasting homocysteine levels

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 oxidase–mediated 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