The role of the antioxidant enzymes in erythrocytes in the development of arterial hypertension among humans exposed to lead

Crucial Interactions between Altered Plasma Trace Elements and Fatty Acids Unbalance Ratio to Management of Systemic Arterial Hypertension in Diabetic Patients: Focus on Endothelial Dysfunction

The coexistence of SAH with T2DM is a common comorbidity. In this study, we investigated the link between altered plasma antioxidant trace elements (ATE: manganese, selenium, zinc, and copper) and fatty acids ratio (FAR: polyunsaturated/saturated) imbalance as transition biomarkers between vascular pathology (SAH) to metabolic pathology (T2DM). Our data revealed strong correlation between plasma ATE and FAR profile, which is modified during SAH-T2DM association compared to the healthy group. This relationship is mediated by lipotoxicity (simultaneously prominent visceral adipose tissue lipolysis, significant flow of non-esterified free fatty acids release, TG-Chol-dyslipidemia, high association of total SFA, palmitic acid, arachidonic acid, and PUFA ω6/PUFA ω3; drop in tandem of PUFA/SFA and EPA + DHA); oxidative stress (lipid peroxidation confirmed by TAS depletion and MDA rise, concurrent drop of Zn/Cu-SOD, GPx, GSH, Se, Zn, Se/Mn, Zn/Cu; concomitant enhancement of Cu, Mn, and Fe); endothelial dysfunction (endotheline-1 increase); athero-thrombogenesis risk (concomitant rise of ApoB100/ApoA1, Ox-LDL, tHcy, and Lp(a)), and inflammation (higher of Hs-CRP, fibrinogen and ferritin). Our study opens to new therapeutic targets and to better dietary management, such as to establishing dietary ATE and PUFA ω6/PUFA ω3 or PUFA/SFA reference values for atherosclerotic risk prevention in hypertensive/diabetic patients.

Boron Compounds Exhibit Protective Effects against Aluminum-Induced Neurotoxicity and Genotoxicity: In Vitro and In Vivo Study

Genetic, neuropathological and biochemical investigations have revealed meaningful relationships between aluminum (Al) exposure and neurotoxic and hematotoxic damage. Hence, intensive efforts are being made to minimize the harmful effects of Al. Moreover, boron compounds are used in a broad mix of industries, from cosmetics and pharmaceuticals to agriculture. They affect critical biological functions in cellular events and enzymatic reactions, as well as endocrinal and mineral metabolisms. There are limited dose-related data about boric acid (BA) and other boron compounds, including colemanite (Col), ulexite (UX) and borax (BX), which have commercial prominence. In this study, we evaluate boron compounds' genetic, cytological, biochemical and pathological effects against aluminum chloride (AlCl3)-induced hematotoxicity and neurotoxicity on different cell and animal model systems. First, we perform genotoxicity studies on in vivo rat bone marrow cells and peripheric human blood cultures. To analyze DNA and chromosome damage, we use single cell gel electrophoresis (SCGE or comet assay) and micronucleus (MN) and chromosome aberration (CA) assays. The nuclear division index (NDI) is used to monitor cytostasis. Second, we examine the biochemical parameters (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), total antioxidant capacity (TAC) and total oxidative status (TOS)) to determine oxidative changes in blood and brain. Next, we assess the histopathological alterations by using light and electron microscopes. Our results show that Al increases oxidative stress and genetic damage in blood and brain in vivo and in vitro studies. Al also led to severe histopathological and ultrastructural alterations in the brain. However, the boron compounds alone did not cause adverse changes based on the above-studied parameters. Moreover, these compounds exhibit different levels of beneficial effects by removing the harmful impact of Al. The antioxidant, antigenotoxic and cytoprotective effects of boron compounds against Al-induced damage indicate that boron may have a high potential for use in medical purposes in humans. In conclusion, our analysis suggests that boron compounds (especially BA, BX and UX) can be administered to subjects to prevent neurodegenerative and hematological disorders at determined doses.

Occupational Health Aspects with Special Focus on Physiological Differences between Office and Metalworkers

Physical workload adversely impacts inflammation, oxidative stress and mood in heavy workers. We compared these risk parameters between metalworkers (n = 20) and office workers (n = 30), including gender differences. Blood samples were analyzed with thirty parameters to overview endocrinology, inflammation, and psychological and oxidative stress. Despite an adequate antioxidative supply, oxidative stress occurred in metalworkers, as indicated by significantly increased peroxide and homocysteine (Hcy) levels. Moreover, increased concentrations were observed in this group regarding psychological stress and diet-related parameters. Sex-specific differences were determined for physical dimensions, dehydroepiandrosterone sulfate (DHEAS), Hcy, uric acid, triglycerides, osmolality, anti-Mullerian hormone (AMH) and testosterone. Age-associated differences were observed for DHEAS, glycosylated hemoglobin, adrenaline, AMH and testosterone. In male office workers, the body mass index was associated with increased LDL-HDL, cholesterol-HDL and homeostatic model assessment of insulin resistance (HOMA-IR). In conclusion, these results indicate increased oxidative stress and psychological stress in heavy workers independently of adequate antioxidant sustenance. The sedentary occupation of office workers, in turn, favored diseases of affluence. This might be particularly relevant for long-term occupied persons and older workers due to a hormonal shift coming along, given the risk for oxidative stress-related diseases such as cardiovascular disease, particularly in the case of males, based on their lifestyle habits.

Association of blood cobalt concentrations with dyslipidemia, hypertension, and diabetes in a US population: A cross-sectional study

Various heavy metal elements in the human body have been reported to be associated with dyslipidemia, hypertension, and diabetes. The role of cobalt in these conditions is unclear. The current study aimed to investigate the association of blood cobalt concentrations with dyslipidemia, hypertension, and diabetes.Using the data collected from the National Health and Nutrition Examination Survey (2015-2018), we performed logistic regression to explore the association of blood cobalt concentrations with total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, hypertension, and diabetes.A total of 6866 adults were included in this study. Participants with higher blood cobalt levels appeared to be older and have a lower body mass index and, were more likely to be female (P for trend < .05). After fully adjusting for demographic characteristics (Model 2), compared with the lowest quartile, the highest quartile of blood cobalt concentrations had lower odds ratios (ORs) for elevated TC [OR: 0.62, 95% confidential interval (CI): 0.53 to 0.72, P < .001], elevated LDL-C (OR: 0.65, 95% CI: 0.53-0.80, P < .001) and low HDL-C (OR: 0.81, 95% CI: 0.69-0.96, P = .013). The adjusted ORs for elevated TC, elevated LDL-C and low HDL-C were negatively correlated with increased blood cobalt concentrations (P for trend < .05). The adjusted ORs for hypertension and diabetes were not associated with blood cobalt concentrations (P > .05 and P for trend > .05).In conclusion, higher blood cobalt concentrations were associated with a lower risk of dyslipidemia. However, blood cobalt concentrations were not associated with the risk of hypertension or diabetes.

Adaptive epigenetic response of glutathione (GSH)-related genes against lead (Pb)-induced toxicity, in individuals chronically exposed to the metal

It is well known that one of the most outstanding adverse effects related to lead (Pb) exposure is oxidative stress; moreover, recent findings suggest that disturbances of the redox status of cells are associated with epigenetic responses, and metabolism of glutathione (GSH) plays an important role in this process. This study aimed to assess Pb exposure on % methylation of GSH-related genes' promoter regions (%CH₃-CpG) and their influence on biomarkers of oxidative stress, in workers exposed to the metal. One hundred nine male workers participated in the study; ICP-MS determined blood lead levels (BLL); biochemical parameters related to redox status, named GSH, glutathione peroxidase (GPX) and glutathione-S-transferase (GST) were quantified by UV/Vis spectrophotometry. Determination of %CH₃-CpG of genes GCLC, GPX1, GSR, and GSTP1 were done by pyrosequencing. Inverse associations were seen between BLL and %CH₃-CpG-GCLC, and %CH₃-CpG-GSTP1. Moreover, metal exposure did not impact GSH, GPX, and GST; however, negative associations were observed between %CH₃-CpG-GPX1 and %CH₃-CpG-GSTP1, and the activities of GPX and GST, respectively. Taken together, our results give further evidence about adaptive epigenetic response to avoid oxidative damage induced by Pb exposure, allowing a better understanding of the molecular mechanisms related to the metal toxicity.

Association between blood lead levels and blood pressure in American adults: results from NHANES 1999-2016

The aim of this study was to investigate the association between blood lead level (BLL) and hypertension in adults when lead exposure for the general population is low. The study used data from the US National Health and Nutrition Examination Survey (NHANES) 1999-2016. Participants aged 20 to 79 years were included in our study. Weighted multiple linear regression and logistic regression were conducted to test the association between BLL and systolic/diastolic blood pressure and hypertension status, respectively, while controlling for age, gender, race/ethnicity, body mass index, income level, and education. A total of 30,467 participants were included in this study. There was no association between BLL and hypertension status for the overall sample. Among those who were not taking antihypertensive medication, after adjusting for covariates, systolic blood pressure was positively correlated with BLL in non-Hispanic Whites (P = 0.004) and non-Hispanic Blacks (P = 0.0005), but not Hispanics (P = 0.07) nor Others (P = 0.37). The relationship between diastolic blood pressure and lead levels was also significant in non-Hispanic Whites and non-Hispanic Blacks. This study showed that higher BLL was associated with higher systolic and diastolic blood pressure in some population groups, but not associated with hypertension status.

The effects of pretreatment with lithium metaborate dihydrate on lipid peroxidation and Ca, Fe, Mg, and K levels in serum of Wistar albino male rats exposed to Cd

Boron and boron compounds have beneficial biological effects. Lithium metaborate dihydrate (LMBDH) is used in many branches of industry. Despite its wide industrial use, there is limited information about its biological effects on antioxidant defense system and trace element homeostasis. Therefore, the aim of this study was to evaluate the in vivo protective effects of LMBDH against CdCl₂-induced oxidative stress and imbalance of some bioelements for the first time. In the study, totally 20 Wistar albino male rats were used. The rats were fed with pellet food and water ad libitum and divided into four groups including five rats in each. Group I was control group (standard pellet food + water + normal saline), Group II was CdCl₂ (4.58 mg/kg/body weight/intraperitoneally/single dose), Group III was LMBDH (15 mg/kg/body weight/day orally, for 5 days), Group IV was CdCl₂ (4.58 mg/kg/body weight/intraperitoneally/single dose in fifth day), and LMBDH (15 mg/kg/body weight/day orally for 5 days). The results showed that CdCl₂ treatment increased blood MDA level and decreased antioxidant enzyme activities and the level of blood GSH compared to control group. Pretreatment with LMBDH significantly decreased MDA levels and increased SOD activity (p < 0.05). In addition, Ca, Fe, and K levels decreased in LMBDH pretreatment group in different statistically levels. However, Mg levels showed an increase in LMBDH pretreatment group. As a result, LMBDH pretreatment decreased MDA status and supported antioxidant system by increasing SOD activity. In addition, it did not exhibit an ameliorative effect on measured bioelement homeostasis.

Genetic polymorphisms associated with reactive oxygen species and blood pressure regulation

Hypertension is the most prevalent cause of cardiovascular disease and kidney failure, but only about 50% of patients achieve adequate blood pressure control, in part, due to inter-individual genetic variations in the response to antihypertensive medication. Significant strides have been made toward the understanding of the role of reactive oxygen species (ROS) in the regulation of the cardiovascular system. However, the role of ROS in human hypertension is still unclear. Polymorphisms of some genes involved in the regulation of ROS production are associated with hypertension, suggesting their potential influence on blood pressure control and response to antihypertensive medication. This review provides an update on the genes associated with the regulation of ROS production in hypertension and discusses the controversies on the use of antioxidants in the treatment of hypertension, including the antioxidant effects of antihypertensive drugs.

Blood Pressure and Lipid Profile in Automechanics in Relation to Lead Exposure

Context

Elevated blood pressure and alterations in lipid and lipoproteins play a major role in the development and progression of cardiovascular diseases.

Aim

This study is aimed at determining the blood pressure and lipid profile in automechanics.

Settings and Design

A total of 120 male subjects between 18 and 55 years of age comprised 60 automechanics and 60 age-matched occupationally unexposed control subjects in Emene, Enugu State, Nigeria.

Subjects and Methods

Four milliliters of fasting blood samples was collected from all subjects, 2 mL of blood was dispensed into K₂-EDTA vacutainer tube for blood lead analysis, while the other 2 mL was dispensed into plain vacutainer tube, allowed to retract, centrifuged, and the serum used for serum lipid profile analysis. Blood pressure was measured using aneroid sphygmomanometer.

Statistical Analysis

Statistical Package for Social Sciences (SPSS) version 21.0 was used for data analysis.

Results

Automechanics had significantly higher values of systolic and diastolic blood pressures compared with the controls. Serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglyceride (TG) were also significantly higher in the automechanics compared with the controls (P < 0.05); serum high-density lipoprotein cholesterol (HDL-C) level, however, did not differ significantly between the two groups (P > 0.05). Blood lead level showed a significant positive correlation (P < 0.05) with systolic and diastolic blood pressures, serum TC, LDL-C, VLDL-C, and TG, with no significant correlation with serum HDL-C (P > 0.05) in the automechanics and no correlation in the controls.

Conclusion

The result of this study indicates that blood pressure is elevated and lipid profile altered in automechanics which suggests that these groups of workers are prone to increased risk of developing hypertension and cardiovascular disorders due to occupational exposure to lead.

The analysis of QT interval and repolarization morphology of the heart in chronic exposure to lead

There are no common recommendations regarding electrocardiographic monitoring in occupationally exposed workers. Therefore, the present study was designed to investigate whether exposure to lead results in an increase of selected electrocardiography (ECG) pathologies, such as QT interval prolongation and repolarization disorders, in occupationally exposed workers. The study group included 180 workers occupationally exposed to lead compounds. The exposed group was divided according to the median of the mean blood lead level (PbBmean) calculated based on a series of measurements performed during 5-year observation period (35 µg/dl) into two subgroups: low exposure (LE, PbBmean = 20.0–35.0 µg/dl) and high exposure (HE, PbBmean = 35.1–46.4 µg/dl). The control group consisted of 69 healthy workers without occupational exposure to lead. ECG evaluation included the analysis of heart rate (HR), QT interval and repolarization abnormalities. Mean QT interval was significantly greater in the exposed population than in the control group by 2%. In the HE group, mean QT interval was significantly greater than in the control group by 4% and significantly different from those noted in the LE group. Positive correlations between QT interval and lead exposure indices were also reported. Besides, there was a negative correlation between HR and blood lead level. Increased concentration of lead in the blood above 35 μg/dl is associated with the QT interval prolongation, which may trigger arrhythmias when combined with other abnormalities, such as long QT syndrome. Therefore, electrocardiographic evaluation should be a part of a routine monitoring of occupationally exposed populations.

The Level of Selenium and Oxidative Stress in Workers Chronically Exposed to Lead

The possible beneficial role of selenium (Se) on the oxidative stress induced by lead (Pb) is still unclear in humans. Therefore, the aim of the present study was to explore the associations among the Se levels, chronic Pb exposure, oxidative stress parameters, and parameters characterizing the function of the antioxidant defense system in men who are occupationally exposed to Pb. Based on the median serum Se concentrations, the 324 study subjects were divided into two subgroups: a subgroup with a low Se level (L-Se) and a subgroup with a high Se level (H-Se). The levels of lead (PbB) and zinc protoporphyrin (ZPP) in the blood and the delta-aminolevulinic acid (ALA) level in the urine served as indices of Pb exposure. The PbB level was significantly lower in the H-Se group compared to that in the L-Se group by 6 %. The levels of 8-hydroxyguanosine and lipofuscin (LPS) and the activity of superoxide dismutase were significantly lower in the H-Se group compared to that in the L-Se group by 17, 19, and 11 %, respectively. However, the glutathione level (GSH) and the activities of glutathione peroxidase (GPx) and catalase were significantly higher by 9, 23, and 3 %. Spearman correlations showed positive associations between the Se level and GPx activity and GSH level. A lower serum Se level in chronically Pb-exposed subjects is associated with higher Pb blood levels and an elevated erythrocyte LPS level, which reflects the intensity of oxidative stress. Besides, in a group of Pb-exposed subjects with lower serum Se level, depleted GSH pool and decreased activity of GPx in erythrocytes were reported. However, the present results are inadequate to recommend Se supplementation for chronic lead exposure at higher doses than would be included in a normal diet except for selenium deficiency.

Lead Exposure and Oxidative Stress: A Systematic Review

Lead is an environmental toxicant that can induce oxidative stress (OS) via reactive oxygen species (ROS) generation, which has been reported as an important mechanism underlying lead toxicity (Gurer and Ercal 2000; Pande and Flora 2002; Kasperczyk et al. 2004a; Farmand et al. 2005; Verstraeten et al. 2008; Wang et al. 2009; Martinez-Haro et al. 2011). OS occurs when the generation of ROS exceeds the antioxidant system's ability to defend cells against oxidized molecules. ROS is a term generally used to refer to free radicals derived from O2 (e.g., superoxide anions [O2-] and hydroxyl radicals [OH-]) or to non-radical species (e.g. hydrogen peroxide [H2O2]) (Halliwell and Cross 1994).

Effects of Lead Exposure and Genetic Polymorphisms on ALAD and GPx Activities in Brazilian Battery Workers

Lead (Pb) is a toxic metal that is widely used by metallurgical industries such as car battery recycling. Exposure to the metal may modify the redox status of the cells and consequently result in changes in activities of important enzymes such as delta-aminolevulinic acid dehydratase (ALAD) and glutathione peroxidase (GPx). Similarly, genetic polymorphisms may modulate the activities of enzymes related to detoxification processes of the metal and may modify Pb body burden. Therefore, the aims of the present study were (i) to evaluate the correlation between blood lead levels (BLL) and activities of the enzymes ALAD and GPx, and (ii) to determine whether activities of these enzymes may be influenced by polymorphisms in ALAD and GPx genes in Brazilian automotive battery workers chronically exposed to Pb, as well as the effects of these polymorphisms on BLL. Our study included 257 participants; BLL were determined by inductively couple plasma-mass spectrometry (ICP-MS), and the activities of the enzymes ALAD and GPx were quantified spectrophotometrically; and genotyping of ALAD (rs1800435) and GPx-1 (rs1800668) polymorphisms was performed by TaqMan assays (real-time polymerase chain reaction, RT-PCR). Significant negative correlations were found between BLL and ALAD activity. Subjects who carried at least one polymorphic allele for ALAD gene displayed markedly lower ALAD activities, while no significant effect was observed regarding GPx-1 polymorphism and activity of the same enzyme. Further, ALAD and GPx-1 polymorphisms exerted no marked influence on BLL. Taken together, our results showed that BLL affected ALAD but not GPx activities, and these were not modulated by polymorphisms in ALAD and GPx gene. Further, the rs1800435 SNP showed a tendency to modulate ALAD activity, while the rs1800668 SNP did not modulate GPx activity in Brazilian automotive battery workers exposed to Pb.

Effects of genetic polymorphisms on antioxidant status and concentrations of the metals in the blood of riverside Amazonian communities co-exposed to Hg and Pb

There have been reports of genetic effects affecting the metabolism of Hg and Pb individually, and thus modulating their toxicities. However, there is still a knowledge gap with respect to how genetics may influence the toxicities of these toxic metals during a co-exposure scenario. This present study is therefore aimed at investigating the effects of polymorphisms in genes (GSTM1, GSTT1, GSTP1, GCLM, GCLC, GPx1, ALAD, VDR and MDR1) that have been implicated in Hg and Pb metabolisms affects the kinetics of these metals, as well as various blood antioxidant status parameters: MDA and GSH, and the activities of CAT, GPx and ALAD among populations that have been co-exposed to both Hg and Pb. Study subjects (207 men; 188 women) were from an Amazonian population in Brazil, exposed to Hg and Pb from diet. The blood levels of Hg and Pb were determined by ICP-MS while genotyping were performed by PCR assays. The median values of Hg and Pb in blood were 39.8µg/L and 11.0µg/dL, respectively. GSTM1, ALAD and VDR polymorphisms influenced Hg in blood (β=0.17; 0.37 and 0.17; respectively, p<0.050) while variations on GCLM, GSTT1 and MDR1 (TT) modulated the concentrations of Pb among the subjects (β=-0.14; 0.13 and -0.22; re-spectively, p<0.050). GSTT1 and GCLM polymorphisms also are associated to changes of MDA concentrations. Persons with null GSTM1 genotype had higher activity of the antioxidant enzyme CAT than carries of the allele. Individuals with deletion of both GSTM1 and GSTT1 had a decreased expression of GPx compared to those that expressed at least, one of the enzymes. ALAD 1/2 subjects had lower ALAD activity than individuals with the non-variant genotype. Our findings give further support that polymorphisms related to Hg and Pb metabolism may modulate Hg and Pb body burden and, consequently metals-induced toxicity.

Environmental lead exposure, catalase gene, and markers of antioxidant and oxidative stress relation to hypertension: an analysis based on the EGAT study

Lead has been linked to the development of hypertension via oxidative stress. Catalase plays an important role in the disposal of hydrogen peroxide in erythrocyte and its activity was determined by CAT gene. The aims of this study were to investigate (1) the association between blood levels of antioxidant markers such as catalase, superoxide dismutase, glutathione, glutathione peroxidase, oxidative stress-marker (malondialdehyde), and blood lead level and (2) the influence of genetic polymorphism of CAT gene (rs769217) on change in blood pressure in general population of EGAT study project. This is a cross-sectional study of 332 normotensive, 432 prehypertensive, and 222 hypertensive male subjects. Hypertensive subjects had significantly higher blood lead level (5.28 μg/dL) compared to normotensive (4.41 μg/dL) and prehypertensive (4.55 μg/dL) subjects (P < 0.05). These significant findings are also found in MDA levels. Moreover, individuals with TT genotype in hypertensive group had significantly higher blood lead and MDA levels (6.06 μg/dL and 9.67 μmol/L) than those with CC genotype (5.32 μg/dL and 8.31 μmol/L, P < 0.05). Our findings suggested that decreased blood catalase activity in this polymorphism together with low level lead exposure induced lipid peroxidation may be responsible for hypertension.

Beneficial effect of sesame oil on heavy metal toxicity

Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissue. Chelation therapy is mainly for the management of heavy metal-induced toxicity; however, it usually causes adverse effects or completely blocks the vital function of the particular metal chelated. Much attention has been paid to the development of chelating agents from natural sources to counteract lead- and iron-induced hepatic and renal damage. Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of proinflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels. Because metal chelating therapy is associated with adverse effects, treating heavy metal toxicity in addition with sesame oil and sesamol may be better alternatives. This review deals with the possible use and beneficial effects of sesame oil and sesamol during heavy metal toxicity treatment.

Cardiopulmonary exercise testing and its relation to oxidative stress in patients with hypertension

An increase in reactive oxygen species has been implicated in the pathologies of hypertension. This study was designed to evaluate antioxidant activity in hypertensive patients and to assess the relationship between oxidative stress and exercise tolerance in hypertensive patients with mild left ventricular diastolic dysfunction (LVDD). A total of 42 patients, aged 51±9 years, with a long history of hypertension and mild LVDD (mitral flow velocities-E/A <1, deceleration time of E >220 ms, and preserved ejection fraction-EF >50%), and 30 controls without cardiovascular disease, aged 50±7 years, underwent cardiopulmonary exercise testing (CPET). Peak oxygen uptake (peak VO(2)), oxygen pulse (VO(2)/heart rate (HR)) and ventilatory anaerobic threshold (VAT) were obtained during CPET. Antioxidant activity of superoxide dismutase (SOD) and glutathione peroxidase in the blood was measured before and after exercise. Reduced peak VO(2) (1715±426 vs. 2083±465 ml min(-1), P<0.001), VO(2)/HR (12.0±2.8 vs. 14.6±3.3 ml per beat, P<0.001) and percentage of peak VO(2) at VAT (55.5±15.8% vs. 64.5±14.7%, P=0.007) were observed in hypertensive patients, compared with controls. Antioxidant protection was significantly attenuated in hypertensive patients, compared with controls, before (945 vs. 1006, P=0.012) and after exercise (954 vs. 1051, P<0.001). The level of SOD before and after exercise was significantly associated with LVDD in hypertensive patients (P=0.012 and 0.02, respectively). In addition, the degree of LVDD before exercise (E/A) influenced the degree of exercise capability (peak VO(2)) (P=0.016). Asymptomatic hypertensive patients with mild LVDD had reduced cardiopulmonary capacity, accurately identified by CPET. The redox state in hypertensive patients was significantly related to LVDD and exercise tolerance. Attenuated antioxidant protection was associated with long-term hypertension.