Jordi Ordóñez-Llanos

Response of oxidative stress biomarkers to a 16-week aerobic physical activity program, and to acute physical activity, in healthy young men and women.

Physical activity (PA) is associated with a reduced risk of coronary heart disease, and may favorably modify the antioxidant-prooxidant balance. This study assessed the effects of aerobic PA training on antioxidant enzyme activity, oxidized LDL concentration, and LDL resistance to oxidation, as well as the effect of acute PA on antioxidant enzyme activity before and after the training period. Seventeen sedentary healthy young men and women were recruited for 16 weeks of training. The activity of superoxide dismutase in erythrocytes (E-SOD), glutathione peroxidase in whole blood (GSH-Px), and glutathione reductase in plasma (P-GR), and the oxidized LDL concentration and LDL composition, diameter, and resistance to oxidation were determined before and after training. Shortly before and after this training period they also performed a bout of aerobic PA for 30 min. The antioxidant enzyme activity was also determined at 0 min, 30 min, 60 min, 120 min, and 24 h after both bouts of PA. Training induces an increase in GSH-Px (27.7%), P-GR (17.6%), and LDL resistance to oxidation, and a decrease in oxidized LDL (-15.9%). After the bout of PA, an increase in E-SOD and GSH-Px was observed at 0 min, with a posterior decrease in enzyme activity until 30-60 min, and a tendency to recover the basal values at 120 min and 24 h. Training did not modify this global response pattern. Regular PA increases endogenous antioxidant activity and LDL resistance to oxidation, and decreases oxidized LDL concentration; 30 min of aerobic PA decreases P-GR and B-GSH-Px activity in the first 30-60 min with a posterior recovery.

N-terminal probrain natriuretic peptide (NT-proBNP) in the emergency diagnosis and in-hospital monitoring of patients with dyspnoea and ventricular dysfunction.

To evaluate the utility of NT‐proBNP in the emergency diagnosis and in‐hospital monitoring of patients with acute dyspnoea and ventricular dysfunction.

The MUSIC Risk score: a simple method for predicting mortality in ambulatory patients with chronic heart failure.

AIMS The prognosis of chronic heart failure (CHF) is extremely variable, although generally poor. The purpose of this study was to develop prognostic models for CHF patients. METHODS AND RESULTS A cohort of 992 consecutive ambulatory CHF patients was prospectively followed for a median of 44 months. Multivariable Cox models were developed to predict all-cause mortality (n = 267), cardiac mortality (primary end-point, n = 213), pump-failure death (n = 123), and sudden death (n = 90). The four final models included several combinations of the same 10 independent predictors: prior atherosclerotic vascular event, left atrial size >26 mm/m(2), ejection fraction < or =35%, atrial fibrillation, left bundle-branch block or intraventricular conduction delay, non-sustained ventricular tachycardia and frequent ventricular premature beats, estimated glomerular filtration rate <60 mL/min/1.73 m(2), hyponatremia < or =138 mEq/L, NT-proBNP >1.000 ng/L, and troponin-positive. On the basis of Cox models, the MUSIC Risk scores were calculated. A cardiac mortality score >20 points identified a high-risk subgroup with a four-fold cardiac mortality risk. CONCLUSION A simple score with a limited number of non-invasive variables successfully predicted cardiac mortality in a real-life cohort of CHF patients. The use of this model in clinical practice identifies a subgroup of high-risk patients that should be closely managed.

Soluble ST2 for Predicting Sudden Cardiac Death in Patients With Chronic Heart Failure and Left Ventricular Systolic Dysfunction

OBJECTIVES We studied whether the measurement of the soluble form of ST2 (sST2), an interleukin-1 receptor family member, could identify heart failure (HF) patients at risk of sudden cardiac death (SCD). BACKGROUND The prediction of SCD remains an important challenge in patients with mild-to-moderate chronic HF. Concentrations of sST2 have been found increased and related to worse long-term outcomes in patients with acute HF. Whether sST2 has a prognostic role in SCD is unknown. METHODS A nested case-control study was performed on 36 cases of SCD and 63 control patients (matched for age, sex, and left ventricular ejection fraction) obtained from the MUSIC (MUerte Súbita en Insuficiencia Cardíaca) registry, a 3-year multicenter registry of ambulatory HF patients (New York Heart Association functional class II to III, left ventricular ejection fraction < or =45%). Demographic, clinical, echocardiographic, electrical, and biochemical data were collected at enrollment. RESULTS Concentrations of sST2 were greater among decedents (0.23 ng/ml [interquartile range 0.16 to 0.43 ng/ml] vs. 0.12 ng/ml [interquartile range 0.06 to 0.23 ng/ml], p = 0.001) and were predictive of experiencing SCD (+0.1 ng/ml, odds ratio: 1.39, 95% confidence interval: 1.09 to 1.78, p = 0.006). On the basis of a combined biomarker status, only 4% of patients experienced SCD for neither sST2 nor N-terminal pro-B-type natriuretic peptide (NT-proBNP) above receiver-operator characteristic-derived cut-off points (0.15 ng/ml and 2,000 ng/l, respectively), 34% for either biomarker above, and 71% for both biomarkers above (p < 0.001 for trend). This combined variable added incremental prognostic value to the multivariable regression model (p < 0.001). CONCLUSIONS Elevated sST2 concentrations are predictive of SCD in patients with chronic HF and provide complementary information to NT-proBNP levels. A combined biomarker approach may have an impact on clinical decision-making.

Electronegative low-density lipoprotein

Purpose of review The occurrence in blood of an electronegatively charged LDL was described in 1988. During the 1990s reports studying electronegative LDL (LDL(-)) were scant and its atherogenic role controversial. Nevertheless, recent reports have provided new evidence on a putative atherogenic role of LDL(-). This review focuses on and discusses these new findings. Recent findings In recent years, LDL(-) has been found to be involved in several atherogenic features through its action on cultured endothelial cells. LDL(-) induces the production of chemokines, such as IL-8 and monocyte chemotactic protein 1, and increases tumor necrosis factor-α-induced production of vascular cell adhesion molecule 1, with these molecules being involved in early phases of leukocyte recruitment. LDL(-) from familial hypercholesterolemic patients also decreases DNA synthesis and intracellular fibroblast growth factor 2 production, which may contribute to impaired angiogenesis and increased apoptosis. In addition, the preferential association of platelet-activating factor acetylhydrolase with LDL(-) has been reported, suggesting a proinflammatory role of this enzyme in LDL(-). Summary Recent findings suggest that LDL(-) could contribute to atherogenesis via several mechanisms, including proinflammatory, proapoptotic and antiangiogenesis properties. Further studies are required to define the role of LDL(-) in atherogenesis more precisely and to clarify mechanisms involved in endothelial cell activation.

Cross-Reactivity of BNP, NT-proBNP, and proBNP in Commercial BNP and NT-proBNP Assays: Preliminary Observations from the IFCC Committee for Standardization of Markers of Cardiac Damage

B-type natriuretic peptide (BNP) is a 32 amino acid cardiac-synthesized hormone that reduces blood pressure and increases sodium excretion (1). Following proteolytic cleavage of proBNP, a 108-amino acid precursor, an N-terminal fragment (NT-proBNP) and BNP are released (2). Increased concentrations of BNP and NT-proBNP can be used clinically to monitor heart failure, but a lack of alignment between commercial BNP and NT-proBNP assays (3) can lead to confusion when clinicians or laboratorians compare results measured for the same analyte on different instruments. Some of this confusion arises from variable assay specificity regarding what peptides are being measured. We studied whether ( a ) BNP assays demonstrated cross-reactivity with NT-proBNP or proBNP, and ( b ) whether NT-proBNP assays demonstrated cross-reactivity with BNP or proBNP, by using 5 commercial BNP and 3 commercial NT-proBNP assays with 2 BNP, 2 NT-proBNP, and 2 proBNP materials. The NPs studied were: Peptide Institute synthetic BNP (aa 77–108), Scios human recombinant BNP (aa 77–108), HyTest human recombinant NT-proBNP (aa 1–76), Roche modified (amidated for stabilization) synthetic NT-proBNP, HyTest human recombinant proBNP (aa 1–108), and Scios glycosylated human recombinant proBNP. BNP assays evaluated were Abbott Architect, Abbott AxSYM, Bayer …

A genomewide exploration suggests a new candidate gene at chromosome 11q23 as the major determinant of plasma homocysteine levels: results from the GAIT project.

Homocysteine (Hcy) plasma level is an independent risk marker for venous thrombosis, myocardial infarction, stroke, congestive heart failure, osteoporotic fractures, and Alzheimer disease. Hcy levels are determined by the interaction of genetic and environmental factors. The genetic basis is still poorly understood, since only the MTHFR 677 C-->T polymorphism has been consistently associated with plasma Hcy levels. We conducted a genomewide linkage scan for genes affecting variation in plasma Hcy levels in 398 subjects from 21 extended Spanish families. A variance-components linkage method was used to analyze the data. The strongest linkage signal (LOD score of 3.01; genomewide P = .035) was found on chromosome 11q23, near marker D11S908, where a candidate gene involved in the metabolism of Hcy (the nicotinamide N-methyltransferase gene [NNMT]) is mapped. Haplotype analyses of 10 single-nucleotide polymorphisms within this gene found one haplotype associated with plasma Hcy levels (P = .0003). Our results, to our knowledge, represent the first genomic scan for quantitative variation in Hcy plasma levels. They strongly suggest that the NNMT gene could be a major genetic determinant of plasma Hcy levels in Spanish families. Since this gene encodes an enzyme involved in Hcy synthesis, this finding would be consistent with known biochemical pathways. These data could be relevant in determining the relationships between Hcy level, cardiovascular disease, osteoporosis, and Alzheimer disease.

Electronegative LDL From Normolipemic Subjects Induces IL-8 and Monocyte Chemotactic Protein Secretion by Human Endothelial Cells

The presence in plasma of an electronegative LDL subfraction [LDL(−)] cytotoxic for endothelial cells (ECs) has been reported. We studied the effect of LDL(−) on the release by ECs of molecules implicated in leukocyte recruitment [interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1)] and in the plasminogen activator inhibitor-1 (PAI-1). LDL(−), isolated by anion-exchange chromatography, differed from nonelectronegative LDL [LDL(+)] in its higher triglyceride, nonesterified fatty acid, apoprotein E and apoprotein C-III, and sialic acid contents. No evidence of extensive oxidation was found in LDL(−); its antioxidant and thiobarbituric acid–reactive substances contents were similar to those of LDL(+). However, conjugated dienes were increased in LDL(−), which suggests that mild oxidation might affect these particles. LDL(−) increased, in a concentration-dependent manner, the release of IL-8 and MCP-1 by ECs and was a stronger inductor of both chemokines than oxidized LDL (oxLDL) or LDL(+). PAI-1 release increased slightly in ECs incubated with both LDL(−) and oxLDL but not with LDL(+). However, no cytotoxic effects of LDL(−) were observed on ECs. Actinomycin D inhibited the release of IL-8 and MCP-1 induced by LDL(−) and oxLDL by up to 80%, indicating that their production is mediated by protein synthesis. Incubation of ECs with N-acetyl cysteine inhibited production of IL-8 and MCP-1 induced by LDL(−) and oxLDL by >50%. The free radical scavenger butylated hydroxytoluene slightly inhibited the effect of oxLDL but did not modify the effect of LDL(−). An antagonist (BN-50730) of the platelet-activating factor receptor inhibited production of both chemokines by LDL(−) and oxLDL in a concentration-dependent manner. Our results indicate that LDL(−) shows proinflammatory activity on ECs and may contribute to early atherosclerotic events.

Electronegative LDL of FH subjects: chemical characterization and induction of chemokine release from human endothelial cells.

Electronegative LDL (LDL(-)) constitutes a plasma subfraction of LDL with proinflammatory properties. Its proportion is increased in familial hypercholesterolemia (FH); however, the characteristics of LDL(-) isolated from FH subjects have not been previously studied. In this work, the composition, oxidative status, and inflammatory capacity on endothelial cells of LDL(-) from FH and normolipemic (NL) subjects were evaluated. LDL(-) from FH was relatively enriched in esterified and free cholesterol and triglyceride, and had lower apoB and phospholipid content compared with the non-electronegative fraction (LDL(+)). LDL(-) also contained increased amounts of apoE, apoC-III, sialic acid, and non-esterified fatty acids (NEFAs). The same was observed in NL subjects, except that esterified cholesterol and phospholipid were similar in LDL(-) and LDL(+). No difference was observed between the two fractions concerning malondialdehyde, fatty acid hydroxides, and antioxidants, thereby indicating the absence of increased oxidation of LDL(-) compared with LDL(+). When LDL(-) (100 mg/l) from NL and FH subjects was incubated for 24 h with human umbilical vein endothelial cells (HUVECs), interleukin 8 (IL-8) and monocyte chemotactic protein 1 (MCP-1) increased twofold in the culture medium compared with LDL(+). Vascular cell adhesion molecule 1 (VCAM-1) expression was not increased by LDL(-). Our data indicate that LDL(-) from FH or NL subjects shows no evidence of increased oxidative modification compared to LDL(+); however, LDL(-) induces twofold the release of chemokines by endothelial cells. This effect, which may contribute to leukocyte recruitment and promote atherogenesis, may be greater in FH subjects in which LDL(-) can be up to eightfold higher than in NL subjects.

Human Apolipoprotein A-II Enrichment Displaces Paraoxonase From HDL and Impairs Its Antioxidant Properties: A New Mechanism Linking HDL Protein Composition and Antiatherogenic Potential

Apolipoprotein A-II (apoA-II), the second major high-density lipoprotein (HDL) apolipoprotein, has been linked to familial combined hyperlipidemia. Human apoA-II transgenic mice constitute an animal model for this proatherogenic disease. We studied the ability of human apoA-II transgenic mice HDL to protect against oxidative modification of apoB-containing lipoproteins. When challenged with an atherogenic diet, antigens related to low-density lipoprotein (LDL) oxidation were markedly increased in the aorta of 11.1 transgenic mice (high human apoA-II expressor). HDL from control mice and 11.1 transgenic mice were coincubated with autologous very LDL (VLDL) or LDL, or with human LDL under oxidative conditions. The degree of oxidative modification of apoB lipoproteins was then evaluated by measuring relative electrophoretic mobility, dichlorofluorescein fluorescence, 9- and 13-hydroxyoctadecadienoic acid content, and conjugated diene kinetics. In all these different approaches, and in contrast to control mice, HDL from 11.1 transgenic mice failed to protect LDL from oxidative modification. A decreased content of apoA-I, paraoxonase (PON1), and platelet-activated factor acetyl-hydrolase activities was found in HDL of 11.1 transgenic mice. Liver gene expression of these HDL-associated proteins did not differ from that of control mice. In contrast, incubation of isolated human apoA-II with control mouse plasma at 37°C decreased PON1 activity and displaced the enzyme from HDL. Thus, overexpression of human apoA-II in mice impairs the ability of HDL to protect apoB-containing lipoproteins from oxidation. Further, the displacement of PON1 by apoA-II could explain in part why PON1 is mostly found in HDL particles with apoA-I and without apoA-II, as well as the poor antiatherogenic properties of apoA-II–rich HDL.