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Exposure to persistent organic pollutants (POPs) may influence telomere length (TL), which is considered as a marker of biological age associated with the risk of chronic disease. We hypothesized that dietary exposure to polychlorinated biphenyls (PCBs) and dioxins could affect TL. Our aim was to evaluate the association of dietary exposure to PCBs and dioxins with TL. In this cross-sectional study of 886 subjects older than 55 y (mean age: 67.7; standard deviation (SD): 6.1; 27% women) from the “Seguimiento Universidad de Navarra” (SUN) project. TL was determined by real-time quantitative polymerase chain reaction and dietary PCBs and dioxins exposure was collected using a validated 136-item Food Frequency Questionnaire. Multivariable linear regression models were used to control for potential confounding factors. Shorter TL was associated with dietary total PCBs (SD of T/S ratio/(ng/day) = −0.30 × 10−7; 95% CI, −0.55 × 10−7 to −0.06 × 10−7), dioxin-like PCBs (DL-PCBs) (SD of T/S ratio/(pg WHO TEQ (Toxic Equivalents)/day) = −6.17 × 10−7; 95% CI, −11.30 × 10−7 to −1.03 × 10−7), and total TEQ exposure (SD of T/S ratio/(pg WHO TEQ/day) = −5.02 × 10−7; 95% CI, −9.44 × 10−7 to −0.61 × 10−7), but not with dioxins (SD of T/S ratio/(pg WHO TEQ/day) = −13.90 × 10−7; 95% CI, −37.70 × 10−7 to 9.79 × 10−7). In this sample of middle-aged and older Spanish adults, dietary exposure to total PCBs and DL-PCBs alone and together with dioxins was associated with shorter TL. Further longitudinal studies, preferably with POPs measured in biological samples, are needed to confirm this finding.

Background Telomere attrition may play an important role in the pathogenesis and severity of type 2 diabetes (T2D), increasing the probability of β cell senescence and leading to reduced cell mass and decreased insulin secretion. Nutrition and lifestyle are known factors modulating the aging process and insulin resistance/secretion, determining the risk of T2D. Objectives The aim of this study was to evaluate the effects of pistachio intake on telomere length and other cellular aging-related parameters of glucose and insulin metabolism. Methods Forty-nine prediabetic subjects were included in a randomized crossover clinical trial. Subjects consumed a pistachio-supplemented diet (PD, 50 E% [energy percentage] carbohydrates and 33 E% fat, including 57 g pistachios/d) and an isocaloric control diet (CD, 55 E% carbohydrates and 30 E% fat) for 4 mo each, separated by a 2-wk washout period. DNA oxidation was evaluated by DNA damage (via 8-hydroxydeoxyguanosine). Leucocyte telomere length and gene expression related to either oxidation, telomere maintenance or glucose, and insulin metabolism were analyzed by multiplexed quantitative reverse transcriptase-polymerase chain reaction after the dietary intervention. Results Compared with the CD, the PD reduced oxidative damage to DNA (mean: −3.5%; 95% CI: −8.07%, 1.05%; P = 0.009). Gene expression of 2 telomere-related genes (TERT and WRAP53) was significantly upregulated (164% and 53%) after the PD compared with the CD (P = 0.043 and P = 0.001, respectively). Interestingly, changes in TERT expression were negatively correlated to changes in fasting plasma glucose concentrations and in the homeostatic model assessment of insulin resistance. Conclusions Chronic pistachio consumption reduces oxidative damage to DNA and increases the gene expression of some telomere-associated genes. Lessening oxidative damage to DNA and telomerase expression through diet may represent an intriguing way to promote healthspan in humans, reversing certain deleterious metabolic consequences of prediabetes. This study was registered at clinicaltrials.gov as NCT01441921.

Oxidative stress constitutes a key molecular mechanism in the development of cardiovascular diseases. A potential relationship between reactive oxygen species (ROS) driven by the NADPH oxidase family (NOX) and the unfolded protein response (UPR) has been postulated. Nevertheless, there is a lack of information about the crosstalk between NOX5 homologue and the UPR in a cardiovascular context. The main aim was to analyze NOX5-mediated ROS effects in the UPR and its importance in cardiovascular diseases. To this effect, we used an adenoviral NOX5-&beta, overexpression model in human aortic endothelial cells (HAEC) and a conditional endothelial NOX5 knock-in mouse. Using expression arrays, we investigated NOX5-induced genomic changes in HAEC. Compared with the control HAEC, 298 genes were differentially expressed. Gene ontology analysis revealed the activation of numerous cellular routes, the most relevant being the UPR pathway. Using real-time PCR and Western Blot experiments, we confirmed that NOX5 overexpression induced changes in the expression of the UPR components, which were associated with increased apoptosis. Moreover, in endothelial-specific NOX5 knock-in mice, we found changes in the expression of the UPR components genes. In these mice, myocardial infarction was performed by permanent coronary artery ligation, however, NOX5 expression was not associated with differences in the UPR components mRNA levels. In these animals, we found significant associations between the UPR components gene expression and echocardiographic parameters. Our data support the idea that NOX5-derived ROS may modulate the UPR pathway in endothelial cells, which might play a relevant role in cardiac physiology.

Obesity is a global health issue associated with insulin resistance and altered lipid homeostasis. It has been described that reactive oxygen species (ROS) derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity are involved in the development of these pathologies. The present study describes the role of endothelial NOX5 expression over adipose tissue by using two experimental systems: NOX5 conditional knock-in mice fed with a high-fat diet and 3T3-L1 adipocytes cultured with conditioned media of NOX5-expressing endothelial cells previously treated with glucose and palmitic acid. Animals expressing NOX5 presented lower body weight gain and less mesenteric and epididymal adipose mass compared to control mice fed with the same diet. NOX5-expressing mice also showed significantly lower glycaemia and improved insulin-induced glucose uptake. In addition, Glut4 and Caveolin 1 (Cav1) expression were significantly increased in the adipose tissue of these animals. Likewise, 3T3-L1 adipocytes treated with conditioned media from NOX5-expressing endothelial cells, incubated with high glucose and palmitic acid, presented a reduction in lipid accumulation and an increase in glucose uptake. Moreover, a significant increase in the expression of Glut4 and Cav1 was also detected in these cells. Taken together, all these data support that, in response to a highly caloric diet, NOX5 endothelial activity may regulate glucose sensitivity and lipid homeostasis in the adipose tissue.

Objective: Aortic valve (AV) calcification plays an important role in the progression of aortic stenosis (AS). MMP-10 (matrix metalloproteinase-10 or stromelysin-2) is involved in vascular calcification in atherosclerosis. We hypothesize that MMP-10 may play a pathophysiological role in calcific AS. Approach and Results: Blood samples (n=112 AS and n=349 controls) and AVs (n=88) from patients undergoing valve replacement were analyzed. Circulating MMP-10 was higher in patients with AS compared with controls ( P S =0.451; P S =0.5045, P S =0.5003, P P Conclusions: MMP-10, which is overexpressed in aortic valve from patients with AS, seems to play a central role in calcification in AS through Akt phosphorylation. MMP-10 could be a new therapeutic target for delaying the progression of aortic valve calcification in AS.

Oxidative stress is a main molecular mechanism that underlies cardiovascular diseases. A close relationship between reactive oxygen species (ROS) derived from NADPH oxidase (NOX) activity and the prostaglandin (PG) biosynthesis pathway has been described. However, little information is available about the interaction between NOX5 homolog-derived ROS and the PG pathway in the cardiovascular context. Our main goal was to characterize NOX5-derived ROS effects in PG homeostasis and their potential relevance in cardiovascular pathologies. For that purpose, two experimental systems were employed: an adenoviral NOX5-&beta, overexpression model in immortalized human aortic endothelial cells (TeloHAEC) and a chronic infarction in vivo model developed from a conditional endothelial NOX5 knock-in mouse. NOX5 increased cyclooxygenase-2 isoform (COX-2) expression and prostaglandin E2 (PGE2) production through nuclear factor kappa-light-chain-enhancer of activated B cells (NF-&kappa, B) in TeloHAEC. Protein kinase C (PKC) activation and intracellular calcium level (Ca++) mobilization increased ROS production and NOX5 overexpression, which promoted a COX-2/PGE2 response in vitro. In the chronic infarction model, mice encoding endothelial NOX5 enhanced the cardiac mRNA expression of COX-2 and PGES, suggesting a COX-2/PGE2 response to NOX5 presence in an ischemic situation. Our data support that NOX5-derived ROS may modulate the COX-2/PGE2 axis in endothelial cells, which might play a relevant role in the pathophysiology of heart infarction.

Telomere shortening and oxidative stress are involved in the pathogenesis of atherosclerosis. Different studies have shown that phagocytic NADPH oxidase is associated with this disease. This study aimed to investigate the association between phagocytic NADPH oxidase and telomere shortening in human atherosclerosis. To assess this potential association, telomere length and phagocytic NADPH oxidase activity were determined by PCR and chemiluminescence, respectively, in a population of asymptomatic subjects free of overt clinical atherosclerosis. We also measured serum 8-hydroxy-2-deoxyguanosine (8-OHdG) levels (an index of oxidative stress) and carotid intima-media thickness (IMT), a surrogate marker of atherosclerosis. After adjusting them for age and sex, telomere length inversely correlated (p &lt, 0.05) with NADPH oxidase-mediated superoxide production, with 8-OHdG values, and with carotid IMT. Interestingly, the asymptomatic subjects with plaques have a lower telomere length (p &lt, 0.05), and higher values of plasma 8-OHdG and superoxide production (p &lt, 0.05). These data were confirmed in a second population in which patients with coronary artery disease showed lower telomere length and higher 8-OHdG and superoxide production than the asymptomatic subjects. In both studies, NADPH oxidase-dependent superoxide production in phagocytic cells was only due to the specific expression of the Nox2 isoform. In conclusion, these findings suggest that phagocytic NADPH oxidase may be involved in oxidative stress-mediated telomere shortening, and that this axis may be critically involved in human atherosclerosis.

BACKGROUND AND AIMS: Matrix metalloproteinases (MMPs) have been implicated in atherosclerosis and vascular calcification. Among them, we reported that MMP10 is present in human atheroma, associated with atherosclerosis. However, it remains unclear whether MMP10 is involved in atherogenesis and vascular calcification. METHODS: MMP10 was measured in serum from patients with subclinical atherosclerosis and analyzed in carotid endarterectomies by immunostaining. ApoE-deficient mice (Apoe-/-) were crossed to MMP10-deficient (Mmp10-/-) mice and followed up to 20 months. Plaque area and composition were assessed by histology and immunohistochemistry. Inflammatory markers were measured in atherosclerotic plaques by RT-qPCR, and leukocyte subpopulations were analyzed by flow cytometry. In vitro calcification assays were performed in aortic vascular smooth muscle cells (VSMC). RESULTS: MMP10 serum levels were associated with coronary calcification in subjects with subclinical atherosclerosis. Immunostaining revealed MMP10 expression in human atheromas, spatially associated with calcification areas, and complicated plaques released higher amounts of MMP10 than non-diseased segments. Interestingly, vascular MMP10 expression was confined to the atherosclerotic lesion in Apoe-/- mice, and Apoe-/-Mmp10-/- showed a substantial reduction in atherosclerotic lesion size, macrophage content and plaque calcification. Reduced local and systemic inflammatory markers could be demonstrated in Apoe-/-Mmp10-/- by gene expression and flow cytometry analysis. Calcium phosphate deposition and vascular calcification markers were downregulated in VSMC from Apoe-/-Mmp10-/- mice. CONCLUSIONS: Delayed plaque progression and altered cellular composition in the absence of MMP10 suggests that MMP10 plays a role in atherosclerosis, favoring inflammation, development and complication of the plaque. Funded through the "UTE project CIMA" (University of Navarra), Ministerio de Educacion y Ciencia (SAF2009-12039, SAF2016-79151-R), Ministerio de Sanidad y Consumo (PI14/01152 and PI15/01807), Sociedad Espanola de Cardiologia, Sociedad Espanola de Arteriosclerosis, Red de Investigacion Cardiovascular RIC (RD12/0042/0009), the gs5: Fondation pour la Recherche Medicale and the Fondation de France. Sí

Summary Background & aims A healthy lifestyle has been associated with longer telomeres, but whether Mediterranean Diet (MeDiet) affect telomere length (TL) has not been fully elucidated yet. Our aim was to assess the relationship between MeDiet and TL in high cardiovascular risk subjects in the context of a randomized nutritional intervention trial. Methods We assessed 520 participants (55–80 years, 55% women) from the PREDIMED-NAVARRA trial. Leukocyte TL was measured by qPCR at baseline and after 5 years of a dietary intervention program where subjects were randomly assigned to a low-fat control diet or to two MeDiets, one supplemented with extra virgin olive oil (MeDiet-EVOO) and the other with mixed nuts (MeDiet-nuts). A validated 14-item questionnaire was used to appraise baseline adherence of participants to the MeDiet. Results Better adherence to MeDiet (as appraised by the 14-item score) was associated with longer basal telomeres in women in the baseline cross-sectional analysis, whereas the opposite was observed in men (P interaction = 0.036). Female subjects who scored 10 points had longer basal telomeres (0.27, 95% CI: 0.03–0.52) than women scoring ≤6 points at the beginning of the study (−0.46, 95% CI: −0.85 to −0.7) (P = 0.003). However, allocation to the MeDiet-nuts group (−0.24, 95% CI: −0.38 to −0.01) was associated with a higher risk of telomere shortening after 5 years of intervention, whereas no differences were found for the MeDiet-EVOO group (0.14, 95% CI: 0.02–0.27), in comparison with the Control group (0.07, 95% CI: −0.08 to 0.23) (P = 0.003 and P = 0.537, respectively). Conclusion A greater baseline adherence to a Mediterranean dietary pattern was associated with longer telomeres only in women. No beneficial effect of the intervention with the MeDiet for the prevention of telomere shortening in comparison with a low-fat diet was observed.

OBJECTIVE Insulin resistance is associated with the pathogenesis of metabolic disorders as type 2 diabetes and obesity. Given the emerging role of signal transduction in these syndromes, we set out to explore the possible role that G protein–coupled receptor kinase 2 (GRK2), first identified as a G protein–coupled receptor regulator, could have as a modulator of insulin responses. RESEARCH DESIGN AND METHODS We analyzed the influence of GRK2 levels in insulin signaling in myoblasts and adipocytes with experimentally increased or silenced levels of GRK2, as well as in GRK2 hemizygous animals expressing 50% lower levels of this kinase in three different models of insulin resistance: tumor necrosis factor-α (TNF-α) infusion, aging, and high-fat diet (HFD). Glucose transport, whole-body glucose and insulin tolerance, the activation status of insulin pathway components, and the circulating levels of important mediators were measured. The development of obesity and adipocyte size with age and HFD was analyzed. RESULTS Altering GRK2 levels markedly modifies insulin-mediated signaling in cultured adipocytes and myocytes. GRK2 levels are increased by ∼2-fold in muscle and adipose tissue in the animal models tested, as well as in lymphocytes from metabolic syndrome patients. In contrast, hemizygous GRK2 mice show enhanced insulin sensitivity and do not develop insulin resistance by TNF-α, aging, or HFD. Furthermore, reduced GRK2 levels induce a lean phenotype and decrease age-related adiposity. CONCLUSIONS Overall, our data identify GRK2 as an important negative regulator of insulin effects, key to the etiopathogenesis of insulin resistance and obesity, which uncovers this protein as a potential therapeutic target in the treatment of these disorders.

Objective To analyze whether genetic variants of PPARA are associated with the development of stage C heart failure. Methods We analyzed the distribution of the rs1800206, rs4253778 and rs135551 polymorphisms in genomic DNA extracted from peripheral blood cells of 534 patients in different heart failure stages and 63 healthy individuals. The mRNA expression of the peroxisome proliferator-activated receptor (PPAR)α target genes long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) and medium-chain acyl-CoA dehydrogenase (MCAD) was measured in myocardial biopsies of a subgroup of stage B and C patients. Functional studies were performed in HL-1 cardiomyocytes. Results The V162 allele of the rs1800206 polymorphism was more frequent in stage C patients than in stage A and B patients and healthy individuals. Patients with the V162 allele exhibited decreased myocardial LCHAD and MCAD mRNA expression as compared to L162 homozygote patients. In addition, stage C patients exhibited lower myocardial LCHAD and MCAD mRNA expression than stage B patients. Cardiomyocytes transfected with the V162 allele presented decreased PPARα transcriptional activity, LCHAD mRNA expression and ATP production compared to cardiomyocytes transfected with the L162 variant. Conclusions These findings suggest that the V162 allele of the human PPARA gene can be a new risk factor in the development of stage C heart failure, likely via depressed cardiac PPARα activity.

OBJECTIVE: Metabolic syndrome (MetS) is associated with insulin resistance and increases the cardiovascular risk. Oxidative stress constitutes a potential mechanism that links insulin resistance and cardiovascular disease. The aim of this study was to analyze the relationship of NADPH oxidase activation with insulin resistance, and the effect of this interaction on the cardiovascular risk in MetS patients. METHODS: NADPH oxidase-dependent superoxide production and expression was evaluated by luminescence and western blot, respectively, in peripheral blood mononuclear cells obtained from 125 patients with MetS. Insulin resistance was defined by the homeostasis model assessment index. Matrix metalloproteinase-9 was quantified by enzyme-linked immunosorbent assay in plasma samples. To ascertain the mechanisms involved in vivo, we performed in-vitro experiments in cultured macrophages. RESULTS: Fifty-six percent of patients with MetS showed insulin resistance. Plasma matrix metalloproteinase-9 levels were higher (P < 0.05) in insulin-resistant patients than in patients with insulin sensitivity. NADPH oxidase-dependent superoxide production was augmented (P < 0.05) in insulin-resistant patients with respect to insulin-sensitive patients. The interaction between insulin resistance and abnormally high NADPH oxidase-mediated superoxide production was associated with the highest matrix metalloproteinase-9 values. Increased NADPH oxidase-dependent superoxide production was significantly associated with higher NADPH oxidase p22phox expression in insulin-resistant than in insulin-sensitive patients. Interestingly, insulin upregulated p22phox in peripheral blood mononuclear cells and in murine macrophages. CONCLUSION: Insulin resistance is associated with phagocytic NADPH oxidase activation. This association results in the highest cardiovascular risk in MetS patients.

Objective— Data suggest that matrix metalloproteinase-9 (MMP-9) has a role in atherosclerosis. The phagocytic NADPH oxidase has been also associated with atherosclerosis. This study aimed to investigate the association between phagocytic NADPH oxidase and MMP-9 in human atherosclerosis. Methods and Results— In vitro experiments performed in human monocytes showed that NADPH oxidase activation enhanced MMP-9 secretion and activity, determined by enzyme-linked immunosorbent assay and zymography, respectively. Immunohistochemical study showed that phagocytic NADPH oxidase localized with MMP-9 in endarterectomies from patients with carotid stenosis. In addition, a positive relationship ( P Conclusions— Enhanced NADPH oxidase-dependent ·O 2 − production stimulates MMP-9 in monocytes and this relationship may be relevant in the atherosclerotic process. Moreover, MMP-9 emerges as an important mediator of the phagocytic NADPH oxidase-dependent oxidative stress in atherosclerosis.

OBJECTIVE: Oxidative stress is implicated in hypertension and the NADPH oxidase systems constitute the main source of superoxide in vascular wall. We searched for new polymorphisms within the CYBA promoter, the human gene that encodes the p22phox protein, and studied their potential association with essential hypertension. DESIGN: A case-control study in a random sample of the general population. METHODS: CYBA polymorphisms were determined by restriction fragment length polymorphism and allelic discrimination. NADPH oxidase activity was quantified in phagocytic cells by chemiluminescence. RESULTS: We identified three novel polymorphisms, at positions -852, -675 and -536 from the ATG codon. Only the -675(A/T) polymorphism associated with essential hypertension. The prevalence of the TT genotype and the T allele frequency were significantly higher (P < 0.05) in hypertensives than in normotensives. Furthermore, TT hypertensives exhibited higher (P < 0.05) systolic blood pressure values than TA/AA hypertensives. Increased phagocytic NADPH oxidase activity was observed in TT subjects compared to TA and AA individuals (P < 0.05). Enhanced carotid intima-media thickness, a surrogate marker of atherosclerosis, was found in TT subjects compared to TA and AA individuals (P < 0.05). Finally, mutagenesis experiments demonstrated a functional role of this polymorphism on the CYBA promoter activity. CONCLUSION: The -675 (A/T) CYBA polymorphism may be a novel genetic marker associated with essential hypertension. Furthermore, TT subjects exhibit features of NADPH oxidase-mediated oxidative stress and asymptomatic atherosclerosis.

OBJECTIVES Cardiotrophin-1 (CT-1) induces hypertrophic growth and contractile dysfunction in cardiomyocytes. This cross-sectional study was aimed to analyze CT-1 associations with echocardiographically assessed left ventricular systolic properties taking into account the influence of left ventricular growth [i.e. left ventricular hypertrophy (LVH) and inappropriate left ventricular mass (iLVM)] in asymptomatic hypertensive patients. METHODS Serum CT-1 was measured by ELISA in 278 asymptomatic hypertensive patients with a left ventricular ejection fraction more than 50% and in 25 age and sex-matched normotensive patients. RESULTS Serum CT-1 was increased in hypertensive patients as compared to normotensive patients. CT-1 was directly correlated with parameters of left ventricular mass (LVM) and inversely correlated with parameters assessing myocardial systolic function and left ventricular chamber contractility in hypertensive patients, these associations being independent of a number of potential confounding factors. Interestingly, the associations of CT-1 with myocardial systolic function were independent of LVM even in patients with LVH or iLVM. In addition, there was a significant increment of serum CT-1 in hypertensive patients with LVH or iLVM, especially in those in whom LVH or iLVM were accompanied by impaired myocardial systolic function, as compared to the remaining hypertensive patients and normotensive patients. Plasma amino-terminal pro-brain natriuretic peptide was not correlated with any of the assessed left ventricular systolic parameters in either group of patients. CONCLUSION These findings suggest that serum CT-1 is associated with myocardial systolic dysfunction in asymptomatic hypertensive patients, independently of LVM, even in those patients with pathologic left ventricular growth.

Oxidative stress plays a critical role in the pathogenesis of atherosclerosis in patients with metabolic syndrome. This study aimed to investigate whether a relationship exists between phagocytic NADPH oxidase activity and oxidative stress and atherosclerosis in metabolic syndrome patients. The study was performed in 56 metabolic syndrome patients (metabolic syndrome group), 99 patients with one or two cardiovascular risk factors (cardiovascular risk factor group), and 28 healthy subjects (control group). NADPH oxidase expression and activity was augmented (P < 0.05) in metabolic syndrome compared with cardiovascular risk factor and control groups. Insulin was enhanced (P < 0.05) in metabolic syndrome patients compared with cardiovascular risk factor and control groups and correlated with NADPH oxidase activity in the overall population. Insulin stimulated NADPH oxidase activity; this effect was abolished by a specific protein kinase C inhibitor. Oxidized LDL and nitrotyrosine levels and carotid intima-media thickness were increased (P < 0.05) in the metabolic syndrome group compared with cardiovascular risk factor and control groups and correlated with NADPH oxidase activity in the overall population. These findings suggest that phagocytic NADPH oxidase overactivity is involved in oxidative stress and atherosclerosis in metabolic syndrome patients. Our findings also suggest that hyperinsulinemia may contribute to oxidative stress in metabolic syndrome patients through activation of NADPH oxidase.

Objective Leptin attenuates the angiotensin II-induced increase of cytosolic calcium ([Ca 2+ ] i ) and vasoconstriction in the aorta of normotensive Wistar rats. To determine whether these effects may be altered in hypertension, we assessed the effect of leptin on angiotensin II-induced vascular response in the aorta of 10-week-old spontaneously hypertensive rats (SHR). Methods Contractile responses to angiotensin II (100 nmol/l) in the presence of different concentrations of leptin (0.1,1, 10, 100 nmol/l) were evaluated in isolated aortic rings by the organ bath system. [Ca 2+ ] i was measured in vascular smooth muscle cells (VSMCs) using Fura-2 fluorescence. The expression of the short (OB-Ra) and long (OB-Rb) isoforms of the leptin receptor in VSMCs was evaluated by real-time reverse transcriptase-polymerase chain reaction and western-blot analysis. Results Circulating leptin concentrations were increased in SHR. Serum metabolic parameters, including glucose, insulin, total cholesterol and triglyceride levels, were also elevated in SHR. Leptin did not modify the angiotensin II-induced vasoconstriction in SHR either in intact or endothelium-denuded aortic rings. In addition, leptin was not able either to diminish the angiotensin II-induced the peak rise of [Ca 2+ ] i or to accelerate the recovery rate to basal calcium levels in VSMCs from SHR. However, OB-Ra and OB-Rb mRNA and protein expression were increased in SHR VSMCs. Conclusions The lack of effect of leptin on angiotensin II-induced contraction in the aorta of SHR is due to an impaired handling of [Ca 2+ ] i in VSMCs. Hyperleptinemia and overexpression of OB-R in VSMCs could be compensatory mechanisms against VSMC leptin resistance in genetically hypertensive rats.

OBJECTIVE: Oxidative stress is implicated in hypertension. The reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases are the main source of superoxide in phagocytic and vascular cells. The C242T polymorphism of CYBA, the human gene that encodes p22phox, has been found to be functionally associated with vascular NADPH oxidase activity in atherosclerotic patients. We investigated the association of the C242T polymorphism with hypertension and its potential impact on NADPH oxidase activity. We also analysed the interaction of C242T polymorphism with the -930A/G CYBA variant. DESIGN: Case-control study in a random sample of 623 subjects (326 hypertensive patients and 297 normotensive controls) from the general population. METHODS: CYBA polymorphisms were determined by restriction fragment length polymorphism (RFLP) or allelic discrimination. NADPH oxidase activity and p22phox expression were quantified in phagocytic cells by chemiluminescence and by northern and western blots, respectively. RESULTS: The prevalence of the CC genotype and the C allele frequency were significantly higher (P < 0.05) in hypertensives than in normotensives. CC genotype remained associated with hypertension after adjusting for potential confounders in a logistic regression analysis. Increased phagocytic NADPH oxidase activity was observed in CC hypertensives compared with CT and TT hypertensives (P < 0.05). Enhanced plasma levels of von Willebrand factor were found in CC hypertensives compared with TT hypertensives (P < 0.05). The C242T polymorphism was not in linkage disequilibrium with the -930A/G CYBA promoter variation, which also associates with hypertension. CONCLUSION: The C242T CYBA polymorphism is associated with essential hypertension. Furthermore, hypertensives carrying the CC genotype of this polymorphism exhibit features of NADPH oxidase-mediated oxidative stress and endothelial damage.

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 P 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.

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 (•O2-) 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 •O2- production between normotensives and hypertensives, the •O2- production in phorbol myristate acetate (PMA)-stimulated mononuclear cells was increased (P < 0.05) in hypertensives compared with normotensives. The PMA-induced •O2- production was completely abolished by apocynin, a specific inhibitor of NADPH oxidase. Moreover, stimulation of •O2- 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 •O2- production and NOx in hypertensives. Conclusions: Generation of •O2- 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.

Hypertensive heart disease is a progressive condition in which the compensatory left ventricular hypertrophy that maintains cardiac output leads to myocardial remodeling, characterized by fibrosis, insufficient vascularization, and alterations in cardiomyocytes, including contractile disturbances, changes in gene expression, and decrease in the number of cells. Structural abnormalities in the myocardial wall accelerate the development of diastolic and systolic dysfunction, resulting in heart failure. Many observations point to the apoptotic cell death of cardiomyocytes as a relevant factor in the transition from compensatory hypertrophy to pump failure in experimental and human hypertension. Potential inducers of cardiomyocyte apoptosis in overloaded hearts include extrinsic factors, such as mechanical forces, neurohormonal activation, oxidative stress, hypoxia, and cytokines. Some lines of evidence indicate that angiotensin II and the overstretching of cardiomyocytes are originally involved in the triggering of apoptosis in hypertension, whereas other factors are being investigated. Furthermore, intracellular changes, such as downregulation of survival proteins or activation of death proteins, seem to play an important role. The assumption that the apoptosis of cardiomyocytes worsens hypertensive heart disease prognosis brings forth new approaches to avoid or slow the transition to pump failure. In this respect, experimental data indicate that currently used antihypertensive drugs interfere with cardiomyocyte apoptosis. Moreover, the knowledge of intracellular apoptotic processes in cardiomyocytes provides novel therapeutic strategies to be added to the multimodal approach in the prevention of heart failure.

Abstract —Torasemide is a loop diuretic that is effective at low once-daily doses in the treatment of arterial hypertension. Because its antihypertensive mechanism of action may not be based entirely on the elimination of salt and water from the body, a vasodilator effect of this drug can be considered. In the present study, the ability of different concentrations of torasemide to modify angiotensin II (Ang II)–induced vascular responses was examined, with the use of an organ bath system, in endothelium-denuded aortic rings from spontaneously hypertensive rats. Ang II–induced increases of intracellular free calcium concentration ([Ca 2+ ] i ) were also examined by image analysis in cultured vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats. A dose-response curve to Ang II was plotted for cumulative concentrations (from 10 −9 to 10 −6 mol/L) in endothelium-denuded aortic rings (pD 2 =7.5±0.3). Isometric contraction induced by a submaximal concentration of Ang II (10 −7 mol/L) was reduced in a dose-dependent way by torasemide (IC 50 =0.5±0.04 μmol/L). Incubation of VSMCs with different concentrations of Ang II (from 10 −10 to 10 −6 mol/L) resulted in a dose-dependent rise of [Ca 2+ ] i (pD 2 =7.5±0.3). The stimulatory effect of [Ca 2+ ] i induced by a submaximal concentration of Ang II (10 −7 mol/L) was blocked by torasemide (IC 50 =0.5±0.3 nmol/L). Our findings suggest that torasemide blocks the vasoconstrictor action of Ang II in vitro. This action can be related to the ability of torasemide to block the increase of [Ca 2+ ] i induced by Ang II in VSMCs. It is proposed that these actions might be involved in the antihypertensive effect of torasemide observed in vivo.

OBJECTIVE: Previous studies have shown that as well as left ventricular hypertrophy, myocardial fibrosis develops early in rats with spontaneous hypertension (SHR). The present study was designed to investigate whether chronic treatment with the angiotensin II type 1 (AT1) receptor antagonist losartan modifies collagen type I metabolism and reverses left ventricular fibrosis in young SHR with left ventricular hypertrophy. DESIGN: The study was performed in 30-week-old normotensive Wistar-Kyoto (WKY) rats, untreated SHR and SHR treated with losartan (20 mg/mg per day, orally) for 14 weeks before they were killed. METHODS: Ventricular pro-alpha 1 (I) collagen messenger RNA was analyzed by Northern blot. Serum levels of the carboxy-terminal propeptide of procollagen type I (PIP) and the pyridoline cross-linked telopeptide domain of collagen type I (CITP) were determined by specific radioimmunoassays as markers of collagen type I synthesis and degradation, respectively. Collagen volume fraction was determined in the left ventricle by quantitative morphometry. RESULTS: Compared with WKY rats, SHR exhibited increased (P < 0.05) mean arterial pressure, pro-alpha 1 (I) collagen messenger RNA, PIP and left ventricular collagen volume fraction, and similar CITP values. After the treatment period, mean arterial pressure was higher (P < 0.05) in losartan-treated SHR than in WKY rats. Compared with untreated SHR, treated SHR showed no left ventricular hypertrophy and diminished (P < 0.05) values of mean arterial pressure, PIP and left ventricular collagen volume fraction. No changes in pro-alpha 1 (I) collagen messenger RNA and CITP values were observed with treatment in SHR. No significant differences in the left ventricular collagen volume fraction were observed between treated SHR with normal blood pressure and treated SHR with abnormally high blood pressure at the end of the treatment period. CONCLUSIONS: These results suggest that chronic AT1 blockade with losartan decreases the post-transcriptional synthesis of fibril-forming collagen type I molecules in young SHR. This effect may be involved in the ability of this drug to reverse left ventricular fibrosis in young rats with genetic hypertension. Apart from its antihypertensive action, other mechanisms may mediate the antifibrotic effect of losartan in this animal model.