Elevated breath pentane in heart failure reduced by free radical scavenger

Exhaled Breath Analysis Using Selected Ion Flow Tube Mass Spectrometry and Disease Severity in Heart Failure

Exhaled breath volatile organic compounds (VOCs) are elevated in heart failure (HF). The ability of VOCs to predict long term cardiovascular mortality and morbidity has not been independently verified. In 55 patients admitted with acute decompensated heart failure (ADHF), we measured exhaled breath acetone and pentane levels upon admission and after 48 h of diuresis. In a separate cohort of 51 cardiac patients undergoing cardiopulmonary exercise testing (CPET), we measured exhaled breath acetone and pentane levels before and at peak exercise. In the ADHF cohort, admission acetone levels correlated with lower left ventricular ejection fraction (LVEF, r = -0.297, p = 0.035). Greater weight loss with diuretic therapy correlated with a greater reduction in both acetone levels (r = -0.398, p = 0.003) and pentane levels (r = -0.309, p = 0.021). In patients with above-median weight loss (≥4.5 kg), patients demonstrated significantly greater percentage reduction in acetone (59% reduction vs. 7% increase, p < 0.001) and pentane (23% reduction vs. 2% reduction, p = 0.008). In the CPET cohort, admission acetone and pentane levels correlated with higher VE/VCO2 (r = 0.39, p = 0.005), (r = 0.035, p = 0.014). However, there were no significant correlations between baseline or peak exercise acetone and pentane levels and peak VO2. In longitudinal follow-up with a median duration of 33 months, patients with elevated exhaled acetone and pentane levels experienced higher composite adverse events of death, ventricular assist device implantation, or orthotopic heart transplantation. In patients admitted with ADHF, higher exhaled breath acetone levels are associated with lower LVEF and poorer outcomes, and greater reductions in exhaled breath acetone and pentane tracked with greater weight loss. Exhaled acetone and pentane may be novel biomarkers in heart failure worthy of future investigation.

Breath analysis combined with cardiopulmonary exercise testing and echocardiography for monitoring heart failure patients: the AEOLUS protocol

This paper describes the AEOLUS pilot study which combines breath analysis with cardiopulmonary exercise testing (CPET) and an echocardiographic examination for monitoring heart failure (HF) patients. Ten consecutive patients with a prior clinical diagnosis of HF with reduced left ventricular ejection fraction were prospectively enrolled together with 15 control patients with cardiovascular risk factors, including hypertension, type II diabetes or chronic ischemic heart disease. Breath samples were collected at rest and during CPET coupled with exercise stress echocardiography (CPET-ESE) protocol by means of needle trap micro-extraction and were analyzed through gas-chromatography coupled with mass spectrometry. The protocol also involved using of a selected ion flow tube mass spectrometer for a breath-by-breath isoprene and acetone analysis during exercise. At rest, HF patients showed increased breath levels of acetone and pentane, which are related to altered oxidation of fatty acids and oxidative stress, respectively. A significant positive correlation was observed between acetone and the gold standard biomarker NT-proBNP in plasma (r= 0.646,p< 0.001), both measured at rest. During exercise, some exhaled volatiles (e.g., isoprene) mirrored ventilatory and/or hemodynamic adaptation, whereas others (e.g., sulfide compounds and 3-hydroxy-2-butanone) depended on their origin. At peak effort, acetone levels in HF patients differed significantly from those of the control group, suggesting an altered myocardial and systemic metabolic adaptation to exercise for HF patients. These preliminary data suggest that concomitant acquisition of CPET-ESE and breath analysis is feasible and might provide additional clinical information on the metabolic maladaptation of HF patients to exercise. Such information may refine the identification of patients at higher risk of disease worsening.

Novel Oxidative Stress Biomarkers with Risk Prognosis Values in Heart Failure

Oxidative stress (OS) is mediated by reactive oxygen species (ROS), which in cardiovascular and other disease states, damage DNA, lipids, proteins, other cellular and extra-cellular components. OS is both initiated by, and triggers inflammation, cardiomyocyte apoptosis, matrix remodeling, myocardial fibrosis, and neurohumoral activation. These have been linked to the development of heart failure (HF). Circulating biomarkers generated by OS offer potential utility in patient management and therapeutic targeting. Novel OS-related biomarkers such as NADPH oxidases (sNox2-dp, Nrf2), advanced glycation end-products (AGE), and myeloperoxidase (MPO), are signaling molecules reflecting pathobiological changes in HF. This review aims to evaluate current OS-related biomarkers and their associations with clinical outcomes and to highlight those with greatest promise in diagnosis, risk stratification and therapeutic targeting in HF.

Lipid Peroxidation in Atherosclerotic Cardiovascular Diseases

Significance: Atherosclerotic cardiovascular diseases (ACVDs) continue to be a primary cause of mortality worldwide in adults aged 35-70 years, occurring more often in countries with lower economic development, and they constitute an ever-growing global burden that has a considerable socioeconomic impact on society. The ACVDs encompass diverse pathologies such as coronary artery disease and heart failure (HF), among others. Recent Advances: It is known that oxidative stress plays a relevant role in ACVDs and some of its effects are mediated by lipid oxidation. In particular, lipid peroxidation (LPO) is a process under which oxidants such as reactive oxygen species attack unsaturated lipids, generating a wide array of oxidation products. These molecules can interact with circulating lipoproteins, to diffuse inside the cell and even to cross biological membranes, modifying target nucleophilic sites within biomolecules such as DNA, lipids, and proteins, and resulting in a plethora of biological effects. Critical Issues: This review summarizes the evidence of the effect of LPO in the development and progression of atherosclerosis-based diseases, HF, and other cardiovascular diseases, highlighting the role of protein adduct formation. Moreover, potential therapeutic strategies targeted at lipoxidation in ACVDs are also discussed. Future Directions: The identification of valid biomarkers for the detection of lipoxidation products and adducts may provide insights into the improvement of the cardiovascular risk stratification of patients and the development of therapeutic strategies against the oxidative effects that can then be applied within a clinical setting.

Metabolic Biomarkers in Heart Failure

Metabolomics is the study of small, organic molecules within biochemical pathways. With advancement of technology, nuclear magnetic resonance, gas chromatography, and mass spectrometry have allowed for the discovery and analysis of large databases of metabolites implicated in heart failure. Metabolomics also explores the patient and environment interactions and unlocks the link between environmental exposures and the development of cardiovascular disease. Although a relatively new field, metabolomics is poised to become a clinically impactful field that develops novel biomarkers and explores new therapeutic interventions in heart failure.

Effects of Diesel Exhaust on Cardiovascular Function and Oxidative Stress

SIGNIFICANCE

Air pollution is a major global health concern with particulate matter (PM) being especially associated with increases in cardiovascular morbidity and mortality. Diesel exhaust emissions are a particularly rich source of the smallest sizes of PM ("fine" and "ultrafine") in urban environments, and it is these particles that are believed to be the most detrimental to cardiovascular health. Recent Advances: Controlled exposure studies to diesel exhaust in animals and man demonstrate alterations in blood pressure, heart rate, vascular tone, endothelial function, myocardial perfusion, thrombosis, atherogenesis, and plaque stability. Oxidative stress has emerged as a highly plausible pathobiological mechanism by which inhalation of diesel exhaust PM leads to multiple facets of cardiovascular dysfunction.

CRITICAL ISSUES

Diesel exhaust inhalation promotes oxidative stress in several biological compartments that can be directly associated with adverse cardiovascular effects.

FUTURE DIRECTIONS

Further studies with more sensitive and specific in vivo human markers of oxidative stress are required to determine if targeting oxidative stress pathways involved in the actions of diesel exhaust PM could be of therapeutic value. Antioxid. Redox Signal. 28, 819-836.

Effects of Trimetazidine on Lipid Peroxidation, Antioxidant Enzyme Activities and Plasma Brain Natriuretic Peptide Levels in Patients with Chronic Cor Pulmonale

An oxidant/antioxidant imbalance in favour of oxidants appears to occur in chronic cor pulmonale (CCP). Oxidative stress could also be a critical event in the pathogenesis of this condition. Trimetazidine (TMZ) has antioxidant properties and may affect the utilization of oxygen radicals. We investigated the effect of TMZ (20 mg three times daily, orally) on activities of erythrocyte malondialdehyde (MDA) and catalase (eCAT), erythrocyte and plasma glutathione peroxidase (GSH-Px) and plasma superoxide dismutase (pSOD) in CCP patients. We also assessed changes in plasma levels of brain natriuretic peptide (BNP) with TMZ therapy.

Sixty CCP patients with significantly higher MDA and markedly lower pSOD, eCAT and GSH-Px (erythrocyte) activities than 24 healthy controls were randomly allocated to receive routine treatment or routine treatment plus TMZ. After 3 months' therapy, greater pSOD, eCAT and GSH-Px (erythrocyte and plasma) activities and lower MDA activity were found with TMZ treatment compared with routine treatment. Plasma BNP levels were significantly lower in TMZ-treated patients and higher in the routine treatment group than in the control group. TMZ improved antioxidant levels, decreased oxidative stress and decreased plasma BNP levels in CCP patients.

Usefulness of Antibodies to Oxidized Low-Density Lipoproteins as Predictors of Morbidity and Prognosis in Heart Failure Patients Aged ≥65 Years

Elevated level of antibodies to oxidized low-density lipoproteins (OxLDL-Ab) was shown to reliably predict morbidity and mortality in patients with heart failure (HF). Two hundred and eleven patients aged ≥65 years treated at the Heart Failure Unit, Tel Aviv-Sourasky Medical Center, were included in this retrospective study. The end points were time to the first hospitalization (morbidity), all-cause mortality, and a combination of the two (composite outcome). HF duration ranged from 8 to 10.5 years. Mean follow-up was 5.2 ± 1.9 years. The mean number of clinical visits was 18.3 ± 2.4. Participants were divided according to OxLDL-Ab level. Group 1 had Ox LDL-Ab level <200 arbitrary U/ml. Group 2 had OxLDL-Ab level ≥200 arbitrary U/ml. The mean time to the first hospitalization was 25.8 ± 17.0 months. The mortality rate was 44.1%. Combined mortality and hospitalization rate was 58.8%. Adjusted hazard ratios of OxLDL-Ab for hospitalization were 3.16, p <0.001, 95% confidence interval 1.740 to 5.736 and for composite outcome 2.67, p <0.001, 95% confidence interval 1.580 to 4.518. In conclusion, OxLDL-Ab level was the best predictor for both hospitalization and composite outcome. It may, thus, serve as a useful clue for early and more accurate detection of poorly controlled HF and as a marker for imminent exacerbations of thereof.

Volatile organic compounds in bile can diagnose malignant biliary strictures in the setting of pancreatic cancer: a preliminary observation

BACKGROUND

Ascertaining the nature of biliary strictures is challenging. The role of volatile organic compounds (VOCs) in bile in determining the cause of biliary strictures is not known.

OBJECTIVE

To identify potential VOCs in the headspaces (gas above the sample) of bile in patients with malignant biliary strictures from pancreatic cancer.

DESIGN

Prospective cross-sectional study.

SETTING

Referral center.

PATIENTS

Prospective study in which bile was aspirated in 96 patients undergoing ERCP for benign and malignant conditions.

MAIN OUTCOME MEASUREMENTS

Selected ion flow tube mass spectrometry (VOICE200R SIFT-MS instrument; Syft Technologies Ltd, Christchurch, New Zealand) was used to analyze the headspace and to build a predictive model for pancreatic cancer.

RESULTS

The headspaces from 96 bile samples were analyzed, including 24 from patients with pancreatic cancer and 72 from patients with benign biliary conditions. The concentrations of 6 compounds (acetaldehyde, acetone, benzene, carbon disulfide, pentane, and trimethylamine [TMA]) were increased in patients with pancreatic cancer compared with controls (P < .05). By using receiver-operating characteristic curve analysis, we developed a model for the diagnosis of pancreatic cancer based on the levels of TMA, acetone, isoprene, dimethyl sulfide, and acetaldehyde. The model [10.94 + 1.8229* log (acetaldehyde) + 0.7600* log (acetone) - 1.1746* log (dimethyl sulfide) + 1.0901* log (isoprene) - 2.1401 * log (trimethylamine) ≥ 10] identified the patients with pancreatic cancer (area under the curve = 0.85), with 83.3% sensitivity and 81.9% specificity.

LIMITATIONS

Sample size.

CONCLUSIONS

The measurement of biliary fluid VOCs may help to distinguish malignant from benign biliary strictures. Further studies are warranted to validate these observations. (Clinical Trial Registration Number NCT01565460.).

The NO/ONOO-cycle as the central cause of heart failure

The NO/ONOO-cycle is a primarily local, biochemical vicious cycle mechanism, centered on elevated peroxynitrite and oxidative stress, but also involving 10 additional elements: NF-κB, inflammatory cytokines, iNOS, nitric oxide (NO), superoxide, mitochondrial dysfunction (lowered energy charge, ATP), NMDA activity, intracellular Ca(2+), TRP receptors and tetrahydrobiopterin depletion. All 12 of these elements have causal roles in heart failure (HF) and each is linked through a total of 87 studies to specific correlates of HF. Two apparent causal factors of HF, RhoA and endothelin-1, each act as tissue-limited cycle elements. Nineteen stressors that initiate cases of HF, each act to raise multiple cycle elements, potentially initiating the cycle in this way. Different types of HF, left vs. right ventricular HF, with or without arrhythmia, etc., may differ from one another in the regions of the myocardium most impacted by the cycle. None of the elements of the cycle or the mechanisms linking them are original, but they collectively produce the robust nature of the NO/ONOO-cycle which creates a major challenge for treatment of HF or other proposed NO/ONOO-cycle diseases. Elevated peroxynitrite/NO ratio and consequent oxidative stress are essential to both HF and the NO/ONOO-cycle.

Redox proteomics identification of oxidatively modified myocardial proteins in human heart failure: implications for protein function

Increased oxidative stress in a failing heart may contribute to the pathogenesis of heart failure (HF). The aim of this study was to identify the oxidised proteins in the myocardium of HF patients and analyse the consequences of oxidation on protein function. The carbonylated proteins in left ventricular tissue from failing (n = 14) and non-failing human hearts (n = 13) were measured by immunoassay and identified by proteomics. HL-1 cardiomyocytes were incubated in the presence of stimuli relevant for HF in order to assess the generation of reactive oxygen species (ROS), the induction of protein carbonylation, and its consequences on protein function. The levels of carbonylated proteins were significantly higher in the HF patients than in the controls (p<0.01). We identified two proteins that mainly underwent carbonylation: M-type creatine kinase (M-CK), whose activity is impaired, and, to a lesser extent, α-cardiac actin. Exposure of cardiomyocytes to angiotensin II and norepinephrine led to ROS generation and M-CK carbonylation with loss of its enzymatic activity. Our findings indicate that protein carbonylation is increased in the myocardium during HF and that these oxidative changes may help to explain the decreased CK activity and consequent defects in energy metabolism observed in HF.

Antibodies to oxidized LDL as predictors of morbidity and mortality in patients with chronic heart failure

BACKGROUND

Oxidative stress appears to play a significant role in the pathogenesis of heart failure (HF). Antibodies to oxidized low-density lipoprotein (Ox LDL Abs) reflect an immune response to LDL over a prolonged period and may thus represent oxidative stress over an extended time. Ox LDL Abs have been shown to correlate with clinical control in HF patients. We evaluated the predictive power of Ox LDL Abs on the outcome in patients with HF.

METHODS AND RESULTS

Baseline levels of Ox LDL Abs were determined by enzyme-linked immunosorbent assay in 284 consecutive outpatients with severe chronic HF who were being treated in the cardiology services of our medical center. Their mean New York Heart Association (NYHA) Class was 2.8. The mean follow-up for the group was 3.7 years, during which 107 (37%) died. The mean time from symptom onset to first hospital admission from HF was 25.8 months. Ox LDL Abs were found to predict morbidity and mortality as evaluated by a Cox multivariate regression analysis with a hazard ration of 1.013 (P < .013), whereas N-terminal pro-B-type natriuretic peptide (NT pro-BNP) levels achieved a HR of 1.028 (P < .099).

CONCLUSIONS

Ox LDL Abs level maybe a useful parameter for monitoring and planning better management of patients with HF. It was superior to pro-BNP as a predictor of clinical course as expressed by time to hospitalization.

Oxidized proteins in plasma of patients with heart failure: role in endothelial damage

BACKGROUND

Oxidative stress is increased in the failing heart, and this might contribute to the pathogenesis of myocardial remodelling and heart failure (HF).

AIM

To identify the oxidized proteins in plasma of chronic HF patients and to evaluate their possible role in endothelial damage.

METHODS

Plasma levels of oxidized proteins were measured by immunoassay and by analysis in albumin and immunoglobulin depleted plasma using a proteomic approach, in 40 HF patients and in 20 age-matched normal subjects. Analysis of the effects of proteins oxidized in vitro on human endothelial cell (EC) viability was also performed.

RESULTS

Plasma levels of oxidized proteins were significantly higher in HF patients than in controls (p<0.01). We identified two proteins, alpha-1-antitrypsin and fibrinogen, which underwent oxidation. Oxidation of alpha-1-antitrypsin resulted in loss of its protease inhibitor activity, thus leading to EC death in the presence of elastase. Fibrinogen, when oxidized, became otherwise cytotoxic and induced apoptosis in EC.

CONCLUSIONS

This study shows that plasma levels of oxidized proteins are increased in HF, and permitted the identification of two proteins, namely alpha-1-antitrypsin and fibrinogen, which underwent oxidation. In vitro results highlighted the potential role of oxidized proteins in the EC damage that occurs in HF.

Exercise Training Normalizes Sympathetic Outflow by Central Antioxidant Mechanisms in Rabbits With Pacing-Induced Chronic Heart Failure

BACKGROUND

In a recent study, we demonstrated that an increase in oxidative stress in the rostral ventrolateral medulla plays a critical role in the sympathoexcitation observed in chronic heart failure (CHF). Growing evidence indicates that exercise training evokes an antioxidative effect in CHF. In the present study, we therefore hypothesized that long-term exercise exerts its beneficial effect on autonomic activity in CHF via central antioxidative mechanisms.

METHODS AND RESULTS

Experiments were performed on New Zealand White rabbits. All rabbits were instrumented to measure mean arterial pressure, heart rate, and renal sympathetic nerve activity and to test baroreflex sensitivity. Exercise training significantly decreased baseline renal sympathetic nerve activity (65.8+/-5.2% to 41.3+/-3.9% of Max [where "Max" is the maximum renal sympathetic nerve activity induced by a 50-mL puff of smoke directed to the external nares of the rabbit], P<0.05) and increased the maximal gain of the baroreflex curves for heart rate (2.2+/-0.2 to 4.6+/-0.7 bpm per mm Hg, P<0.01) and renal sympathetic nerve activity (1.9+/-0.2% to 4.5+/-0.4% of Max per mm Hg, P<0.01) in CHF rabbits. Exercise training increased expression of CuZn superoxide dismutase (0.3+/-0.1 to 1.5+/-0.3 [ratio of CuZn superoxide dismutase to tubulin], P<0.01) and decreased NAD(P)H oxidase subunit gp91(phox) protein expression (1.9+/-0.2 to 1.2+/-0.1 [ratio of gp91(phox) to tubulin], P<0.05) in the rostral ventrolateral medulla of CHF rabbits. Central overexpression of CuZn superoxide dismutase dose-dependently decreased baseline renal sympathetic nerve activity (control, 68.5+/-7.1% of Max; 10(10) particles of adenovirus, 53.2+/-4.4% of Max; and 10(11) particles of adenovirus, 33.7+/-3.5% of Max; P<0.05) in CHF rabbits.

CONCLUSIONS

These results suggest that an upregulation in central antioxidative mechanisms and suppressed central prooxidant mechanisms may contribute to the exercise training-induced beneficial effects on autonomic activity in CHF.

Micronutrients and their supplementation in chronic cardiac failure. An update beyond theoretical perspectives

Physicians' use of micronutrients to improve symptoms or outcomes in chronic illness has until recently been guided by limited data on the actions of individual agents in vitro or in animal studies. However several recently published clinical trials have provided information about which groups of patients are likely to benefit from which combination of micronutrients. Patients with chronic cardiac failure (CCF), particularly elderly individuals, have several reasons to be deficient in micronutrients including reduced intake, impaired gastrointestinal absorption and increased losses on the background of increased utilisation due for example to increased oxidative stress. Studies of nutritional supplementation in CCF patients have usually concentrated on specific agents. However given that many micronutrients have synergistic influences upon metabolic processes this strategy might merely lead to a shifting of a limiting step. Rather, a strategy of increasing the availability of multiple agents at once might be more logical. The aim of this article is to briefly review the experimental rationale for each of the micronutrients of potential benefit in chronic heart failure and examine the current clinical trial evidence supporting their use.

Lipid peroxidation is not increased in heart failure patients on modern pharmacological therapy

BACKGROUND

Previous studies support a role of oxygen-free radicals in the development of congestive heart failure (CHF). The aim of this study was to investigate whether lipid peroxidation is increased in CHF patients on modern pharmacological therapy and whether there is a positive correlation between plasma levels of markers of lipid peroxidation and severity of heart failure (HF). Plasma malondialdehyde (MDA) and isoprostanes are often used as markers of lipid peroxidation and oxidative stress. We also studied whether long-term treatment with isosorbide-5-mononitrate (IS-5-MN) in combination with standard HF therapy affects P-MDA levels in patients with evidence of left ventricular (LV) dysfunction following acute myocardial infarction (AMI).

MATERIALS AND METHODS

Ninety-two patients with clinical or echocardiographic evidence of LV-dysfunction following AMI were randomized to treatment with either IS-5-MN or placebo. In a subgroup of 83 patients with available plasma MDA, echocardiography, right-heart catherization, and plasma natriuretic peptides were evaluated. Control subjects were 80 healthy blood donors. A second study group consisted of 56 patients with CHF, evaluated with respect to LV function, brain natriuretic peptide and markers of oxidative stress (P-MDA and 8-isoprostane). The second control group comprised 50 healthy subjects.

RESULTS

Lipid peroxidation measured by P-MDA and 8-isoprostane was not increased in patients with LV dysfunction treated with standard HF therapy. No positive correlation was found to the severity of HF. Long-term IS-5-MN therapy did not influence P-MDA concentrations.

CONCLUSIONS

Although results from many experimental and clinical studies suggest that oxidative stress is increased in HF, this may not be true for patients treated with beta blockers and inhibitors of the renin-angiotensin system.

Usefulness of anti-oxidized LDL antibody determination for assessment of clinical control in patients with heart failure

BACKGROUND

It has been suggested that oxidative stress may play a role in the pathogenesis of heart failure, this may have potential implications for therapeutic strategies. However, measures of oxidative stress are subject to confounding inaccuracies. IgG antibodies to oxidized LDL reflect exposure to the lipoprotein over an extended period and may thus mirror oxidative stress over a prolonged time frame. Therefore, we tested the hypothesis that anti-oxLDL antibodies correlate with the control of heart failure (HF), as manifested by hospital admissions for cardiac dysfunction.

METHODS

One hundred and two consecutive patients attending the HF clinic with either systolic or diastolic HF were enrolled and the quality of clinical control was evaluated by assessing hospital admissions over the year prior to index determination of the oxidative stress marker. Antibodies to oxLDL were determined by ELISA and pro-BNP levels were also measured.

RESULTS

Most patients (mean age 71.5 years) had systolic HF; mean NYHA functional class was 2.7 and mean left ventricular ejection fraction was 39.7%. Anti-oxLDL antibodies, but not pro-BNP, correlated significantly with mean NYHA score (averaged from all clinic visits in the year prior to blood testing), and with hospital admissions over the year prior to blood testing. Mean IgG anti-oxLDL antibody levels in patients with hospital admissions were 3.4 times higher than those in subjects not hospitalized over the previous year.

CONCLUSION

IgG anti-oxLDL antibody levels correlate with the severity of HF.

Breath ethanol and acetone as indicators of serum glucose levels: an initial report

BACKGROUND

Many volatile organic compounds are present in exhaled breath and may represent by-products of endogenous biological processes. Ethanol is produced via alcoholic fermentation of glucose by gut bacteria and yeast, while acetone derives from oxidations of free fatty acids, influenced by glucose metabolism. We hypothesized that the integrated analysis of breath ethanol and acetone would provide a good approximation of the blood glucose profile during a glucose load.

METHODS

We collected simultaneous exhaled breath gas, ambient air, and serum glucose and insulin samples from 10 healthy volunteers at baseline and during an oral glucose tolerance test (OGTT) (ingestion of 75 g of glucose followed by 120 min of sampling). Gas samples were analyzed by gas chromatography/mass spectrometry.

RESULTS

Mean glucose values displayed a typical OGTT pattern (rapid increase, peak values at 30-60 min, and gradual return to near baseline by 120 min). Breath ethanol displayed a similar pattern early in the test, with peak values at 30 min; this was followed by a fast return to basal levels by 60 min. Breath acetone decreased progressively below basal levels, with lowest readings obtained at 120 min. A multiple regression analysis of glucose, ethanol, and acetone was used to estimate glucose profiles that correlated with measured glucose values with an average individual correlation coefficient of 0.70, and not lower than 0.41 in any subject.

CONCLUSION

The integrated analysis of multiple exhaled gases may serve as a marker of blood glucose levels. Further studies are needed to assess the usefulness of this method in different populations.

Diagnostic potential of breath analysis--focus on volatile organic compounds

Breath analysis has attracted a considerable amount of scientific and clinical interest during the last decade. In contrast to NO, which is predominantly generated in the bronchial system, volatile organic compounds (VOCs) are mainly blood borne and therefore enable monitoring of different processes in the body. Exhaled ethane and pentane concentrations were elevated in inflammatory diseases. Acetone was linked to dextrose metabolism and lipolysis. Exhaled isoprene concentrations showed correlations with cholesterol biosynthesis. Exhaled levels of sulphur-containing compounds were elevated in liver failure and allograft rejection. Looking at a set of volatile markers may enable recognition and diagnosis of complex diseases such as lung or breast cancer. Due to technical problems of sampling and analysis and a lack of normalization and standardization, huge variations exist between results of different studies. This is among the main reasons why breath analysis could not yet been introduced into clinical practice. This review addresses the basic principles of breath analysis and the diagnostic potential of different volatile breath markers. Analytical procedures, issues concerning biochemistry and exhalation mechanisms of volatile substances, and future developments will be discussed.

Current and future uses of breath analysis as a diagnostic tool

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.

Oxidative stress in cardiovascular disease: myth or fact?

Oxidative stress is a mechanism with a central role in the pathogenesis of atherosclerosis, cancer, and other chronic diseases. It also plays a major role in the aging process. Ischemic heart disease is perhaps the human condition in which the role of oxidative stress has been investigated in more detail: reactive oxygen species and consequent expression of oxidative damage have been demonstrated during post-ischemic reperfusion in humans and the protective role of antioxidants has been validated in several experimental studies addressing the pathophysiology of acute ischemia. Although an impressive bulk of experimental studies substantiate the role of oxidative stress in the progression of the damage induced by acute ischemia, not a single pathophysiologic achievement has had a significant impact on the treatment of patients and randomized, controlled clinical trials, both in primary and secondary prevention, have failed to prove the efficacy of antioxidants in the treatment of ischemic cardiovascular disease. This dichotomy, between the experimental data and the lack of impact in the clinical setting, needs to be deeply investigated: certainly, the pathophysiologic grounds of oxidative stress do maintain their validity but the concepts of the determinants of oxidative damage should be critically revised. In this regard, the role of intermediate metabolism during myocardial ischemia together with the cellular redox state might represent a promising interpretative key.

Uremia-related metabolic cardiac risk factors in chronic kidney disease

Growing evidence has been gathered over the last 15 years regarding the role of nontraditional or uremia-related risk factors in the pathogenesis of atherosclerosis in subjects with renal failure. Among those factors, dyslipidemia, inflammation, hyperhomocysteinemia, and oxidant stress have been extensively studied. However, the clinical significance of many of these factors remains controversial in light of reported studies. In this article, the existing evidence regarding the role of uremia-related risk factors in the pathogenesis of atherosclerosis is reviewed, with special emphasis on prevalence, cardiac risk, and management in patients with chronic kidney disease (CKD). Consensus treatment recommendations are provided for risk factors for which there is evidence to support preventive or therapeutic interventions.

Breath markers of oxidative stress in patients with unstable angina

Cardiac chest pain is accompanied by oxidative stress, which generates alkanes and other volatile organic compounds (VOCs). These VOCs are excreted in the breath and could potentially provide a rational diagnostic marker of disease. The breath methylated alkane contour (BMAC), a 3-dimensional surface plot of C4-C20 alkanes and monomethylated alkanes, provides a comprehensive set of markers of oxidative stress. In this pilot study, we compared BMACs in patients with unstable angina pectoris and in healthy volunteers. Breath VOCs were analyzed in 30 patients with unstable angina confirmed by coronary angiography and in 38 age-matched healthy volunteers with no known history of heart disease (mean age +/- SD, 62.7 +/- 12.3 years and 62.5 +/- 10.0, not significant). BMACs in both groups were compared to identify the combination of VOCs that provided the best discrimination between the 2 groups. Forward stepwise entry discriminant analysis selected 8 VOCs to construct a predictive model that correctly classified unstable angina patients with sensitivity of 90% (27 of 30) and specificity of 73.7% (28 of 38). On cross-validation, sensitivity was 83.3% (25 of 30) and specificity was 71.1% (27 of 38). We conclude that the breath test distinguished between patients with unstable angina and healthy control subjects.

Acute and chronic endothelial dysfunction: implications for the development of heart failure

Heart failure has been characterized by a reduction in cardiac contractile function resulting in reduced cardiac output. The clinical symptoms including mild tachycardia, reduced arterial pressure, increased venous or filling pressure and exercise intolerance have conceptually, to a large degree, been attributed to cardiac myocyte dysfunction. More recently, a vascular component has been recognized to contribute to heart failure. Among the most studied vascular mechanisms that might contribute to the development of heart failure has been the reduced production of nitric oxide or the reduced bioactivity of NO associated with both basic models of heart failure and disease in patients. The still evolving concept that heart failure is a cytokine activated state has, in addition, focused attention on the possibility that the cytokine driven isoform of NO synthase (NOS), iNOS, may produce sufficient quantities of NO to actually suppress cardiac myocyte function contributing to the reduced inotropic state in the failing heart. Thus, our view of the role of NO in the development of heart failure has evolved from simply a reduction in production of NO in blood vessels, to altered substrate availability (i.e. L-arginine), to increased scavenging of NO by superoxide anion, to increased production of NO from iNOS. As these concepts develop, our approach to the therapeutics of heart failure has also progressed with the recognition of the need to develop treatments directed towards addressing one or more of these etiologies. This review will focus on these aspects of the involvement of NO in the development of heart failure and some of the treatments that have developed from our understanding of the basic biology of NO to address these pathohysiologic states.

Aldosterone-induced inflammation in the rat heart : role of oxidative stress

Heart failure and hypertension have each been linked to an induction of oxidative stress transduced by neurohormones, such as angiotensin II and catecholamines. Herein, we hypothesized that aldosterone (ALDO) likewise induces oxidative stress and accounts for a proinflammatory/fibrogenic phenotype that appears at vascular and nonvascular sites of injury found in both right and left ventricles in response to ALDO/salt treatment and that would be sustained with chronic treatment. Uninephrectomized rats received ALDO (0.75 micro g/hour) together with 1% dietary NaCl, for 3, 4, or 5 weeks. Other groups received this regimen in combination with an ALDO receptor antagonist, spironolactone (200 mg/kg p.o. daily), or an antioxidant, either pyrrolidine dithiocarbamate (PDTC) (200 mg/kg s.c. daily) or N-acetylcysteine (NAC) (200 mg/kg i.p. daily). Unoperated and untreated age- and gender-matched rats served as controls. We monitored spatial and temporal responses in molecular and cellular events using serial, coronal sections of right and left ventricles. Our studies included: assessment of systolic blood pressure; immunohistochemical detection of NADPH oxidase expression and activity; analysis of redox-sensitive nuclear factor-kappaB activation; in situ localization of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha mRNA expression; monitoring cell growth and infiltration of macrophages and T cells; and analysis of the appearance and quantity of fibrous tissue accumulation. At week 3 of ALDO/salt treatment and comparable to controls, there was no evidence of oxidative stress or pathological findings in the heart. However, at weeks 4 and 5 of treatment, increased gp91(phox) and 3-nitrotyrosine expression and persistent activation of RelA were found in endothelial cells and inflammatory cells that appeared in the perivascular space of intramural coronary arteries and at sites of lost cardiomyocytes in both ventricles. Coincident in time and space with these events was increased mRNA expression of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha. Macrophages, lymphocytes, and proliferating endothelial and vascular smooth muscle cells and fibroblast-like cells were seen at each of these sites, together with an accumulation of fibrillar collagen, or fibrosis, as evidenced by a significant increase in ventricular collagen volume fraction. Co-treatment with spironolactone, PDTC, or NAC attenuated these molecular and cellular responses as well as the appearance of fibrosis at vascular and nonvascular sites of injury. Furthermore, elevated systolic blood pressure in ALDO-treated rats was partially suppressed by spironolactone or either antioxidant. Thus, chronic ALDO/salt treatment is accompanied by a time-dependent sustained activation of NADPH oxidase with 3-nitrotyrosine generation and nuclear factor-kappaB activation expressed by endothelial cells and inflammatory cells. This leads to a proinflammatory/fibrogenic phenotype involving vascular and nonvascular sites of injury found, respectively, in both normotensive and hypertensive right and left ventricles. Spionolactone, PDTC, and NAC each attenuated these responses suggesting ALDO/salt induction of oxidative/nitrosative stress is responsible for the appearance of this proinflammatory phenotype.

Nutritional abnormalities contributing to cachexia in chronic illness

Cachexia is a common consequence of chronic illness. The nutritional abnormalities contributing to the clinical picture are often a composite of reduced appetite, dietary factors including protein, energy and micronutrient intake, malabsorption and increased consumption or loss of nutrients. In this article, using chronic heart failure as an example, we have reviewed the potential influences of chronic disease on each of these and how they might lead to the relentless progression of wasting and the poor prognosis associated with it.

Oxidant injury in coronary heart disease (Part-I)

Oxidative stress damages the heart through a series of reactions beginning with lipid peroxidation, the main process behind atherosclerosis. Antioxidant supplementation has some beneficial effects by binding with metal ions or catalysts to prevent oxidative lipid peroxidation and chain production.

Decreased oxidative stress in patients with idiopathic dilated cardiomyopathy one year after immunoglobulin adsorption

OBJECTIVES

In a substudy to a recently reported investigation that demonstrated the benefit of immunoglobulin adsorption (immunoadsorption) for patients with idiopathic dilated cardiomyopathy (IDC), we tested whether this benefit is associated with a reduction of oxidative stress.

BACKGROUND

The progression of cardiomyopathy is believed to be related to the increase of oxidative stress. Therefore, reduction of oxidative stress could be one of the effects of immunoadsorption for improvement of cardiac performance and clinical status.

METHODS

Plasma markers for oxidative stress-thiobarbituric acid-reactive substances (TBARS), lipid peroxides (LPO), anti-oxidized low-density lipoprotein-autoantibodies (anti-oxLDL-AB), thiol groups and vitamin E-were compared in 31 patients, of whom 16 underwent immunoadsorption and 15 received conventional treatment (controls). All patients received a daily supplement of vitamins, minerals and trace elements.

RESULTS

After one year, TBARS (p = 0.026), LPO (p = 0.026) and anti-oxLD

Physical training in patients with chronic heart failure enhances the expression of genes encoding antioxidative enzymes

OBJECTIVES

We sought to determine whether the benefit of training for vasodilation in the skeletal muscle vasculature of patients with chronic heart failure (CHF) is likely to be caused at the molecular level primarily by increased nitric oxide (NO) production or decreased inactivation of NO.

BACKGROUND

Physical training reverses endothelium dysfunction in patients with CHF, mediated by increased NO bioactivity. Some animal studies support a mechanism whereby training results in increased vascular NO levels by sustained transcriptional activation of the endothelial NO synthase (eNOS) gene, presumably due to shear stress. The mechanism has not been addressed in patients with CHF.

METHODS

The steady state transcript levels for eNOS and two other shear stress regulated genes (angiotensin-converting enzyme [ACE] and prostacyclin synthase [PGI2S]) were measured in samples of skeletal muscle from patients with CHF before and after 12 weeks of training. Transcript levels were measured in the same samples for two genes encoding antioxidant enzymes, copper zinc superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase (GSH-Px). Untrained patients served as controls.

RESULTS

As expected, training significantly enhanced peak oxygen uptake in the patients with CHF. Training did not increase steady-state transcript levels for eNOS, ACE or PGI2S. In striking contrast, training increased the expression of the antioxidative enzyme genes by approximately 100%.

CONCLUSIONS

Our results do not support a model of benefit from training by increased eNOS expression. However, the data are entirely consistent with the alternative hypothesis, that reduced oxidative stress may account for the increase in vascular NO-mediated vasodilation. Insight into the mechanism may be relevant when considering therapies for exercise-intolerant patients with CHF.

CO(2)-controlled sampling of alveolar gas in mechanically ventilated patients

A newly designed gas-sampling device using end-tidal CO(2) to separate dead space gas from alveolar gas was evaluated in 12 mechanically ventilated patients. For that purpose, CO(2)-controlled sampling was compared with mixed expiratory sampling. Alveolar sampling valves were easily controlled via CO(2) concentration. Concentrations of four volatile substances were determined in the expired and inspired gas. Isoflurane and isoprene, which did not occur in the inspired air, had ratios of end-tidal to mixed expired concentrations of 1.75 and 1.81, respectively. Acetone and pentane, found in both the inspired and expired air, showed ratios of 0.96 and 1.0, respectively. Precision of concentration measurements was between 2.4% (isoprene) and 11.2% (isoflurane); reproducibility (as coefficient of variation) was 5%. Because the only possible source of isoflurane and isoprene in this setting was patients' blood, selective enrichment of alveolar gas was demonstrated. By using the new sampling technique, sensitivity of breath analysis was nearly doubled.

A controlled clinical trial of vitamin E supplementation in patients with congestive heart failure

BACKGROUND

Oxidative stress is increased in patients with congestive heart failure and can contribute to the progressive deterioration observed in these patients. Increased oxidative stress is the result of either an increased production of free radicals or a depletion of endogenous antioxidants, such as vitamin E.

OBJECTIVE

We aimed to determine whether vitamin E supplementation of patients with advanced heart failure would modify levels of oxidative stress, thereby preventing or delaying the deterioration associated with free radical injury.

DESIGN

Fifty-six outpatients with advanced heart failure (New York Heart Association functional class III or IV) were enrolled in a double-blind randomized controlled trial for 12 wk. At a baseline visit and at 2 follow-up visits, blood and breath samples were collected for the measurement of indexes of heart function and disease state, including malondialdehyde, isoprostanes, and breath pentane and ethane. Quality of life was also assessed at baseline and after 12 wk of treatment.

RESULTS

Vitamin E treatment significantly increased plasma concentrations of alpha-tocopherol in the treatment group but failed to significantly affect any other marker of oxidative stress or quality of life. In addition, concentrations of atrial natriuretic peptide (a humoral marker of ventricular dysfunction), neurohormonal-cytokine markers of prognosis, tumor necrosis factor, epinephrine, and norepinephrine were unchanged with treatment and were not significantly different from those in the control group.

CONCLUSION

Supplementation with vitamin E did not result in any significant improvements in prognostic or functional indexes of heart failure or in the quality of life of patients with advanced heart failure.

Neutrophil superoxide anion--generating capacity, endothelial function and oxidative stress in chronic heart failure: effects of short- and long-term vitamin C therapy

OBJECTIVES

First, we sought to study the effects of short- and long-term vitamin C therapy on oxidative stress and endothelial dysfunction in chronic heart failure (CHF), and second, we sought to investigate the role of neutrophils as a cause of oxidative stress in CHF.

BACKGROUND

Oxidative stress may contribute to endothelial dysfunction in CHF. Vitamin C ameliorates endothelial dysfunction in CHF, presumably by reducing oxidative stress, but this is unproven.

METHODS

We studied 55 patients with CHF (ischemic and nonischemic etiologies) and 15 control subjects. Flow-mediated dilation (FMD) in the brachial artery was measured by ultrasound wall-tracking, neutrophil superoxide anion (O2-) generation by lucigenin-enhanced chemiluminescence and oxidative stress by measurement of free radicals (FRs) in venous blood using electron paramagnetic resonance (EPR) spectroscopy and plasma thiobarbituric acid reactive substances (TBARS). Measurements were performed at baseline in all subjects. The effects of short-term (intravenous) and long-term (oral) vitamin C therapy versus placebo were tested in patients with nonischemic CHF.

RESULTS

At baseline, FRs were higher in patients with CHF than in control subjects (p < 0.01), TBARS were greater (p < 0.005), neutrophil O2- -generating capacity was enhanced (p < 0.005) and FMD was lower (p < 0.0001). Compared with placebo, short-term vitamin C therapy reduced FR levels (p < 0.05), tended to reduce TBARS and increased FMD (p < 0.05), but did not affect neutrophil O2- -generating capacity. Long-term vitamin C therapy reduced FR levels (p < 0.05), reduced TBARS (p < 0.05) and improved FMD (p < 0.05), but also reduced neutrophil O2- -generating capacity (p < 0.05). Endothelial dysfunction was not related to oxidative stress, and improvements in FMD with vitamin C therapy did not relate to reductions in oxidative stress.

CONCLUSIONS

Oxidative stress is increased in ischemic and nonischemic CHF, and neutrophils may be an important cause. Vitamin C reduces oxidative stress, increases FMD and, when given long term, decreases neutrophil O2- generation, but the lack of a correlation between changes in endothelial function and oxidative stress with vitamin C implies possible additional non-antioxidant benefits of vitamin C.

Effects of captopril on interleukin-6, leukotriene B(4), and oxidative stress markers in serum and inflammatory exudate of arthritic rats: evidence of antiinflammatory activity

We previously demonstrated that captopril (CP) exhibited a high ability to inhibit enzymatically generated leukotrienes, particularly LTB(4), from stimulated intact human neutrophils. This finding together with the immunosuppressive effect of CP have proposed a possible antiinflammatory activity for the drug. Thus, the present study was conducted to investigate the effect of CP on immunologically mediated chronic inflammation; two models were chosen, namely, Freund's adjuvant arthritis and mixed-type hypersensitivity in rat. The effect of CP was assessed on the basis of physical parameter (paw edema) and biochemical markers in blood and inflammatory exudate. CP was given daily during the course of inflammation development. It was administered ip at three doses, viz. 1, 10, and 100 mg/kg. The results claimed that CP succeeded in suppressing edema evolution in hind paws of Freund's arthritic animals, during all phases of the disease. During the chronic phase of inflammation, in either model, CP reduced the elevated serum and exudate (local) LTB(4) and IL-6 levels. The effect on LTB(4) was more pronounced in the exudate and tended to be dose-related. The antiarthritic effect of CP was also accompanied by augmentation of serum level of protein thiols, with reduction or normalization of elevated systemic and/or local levels of lipid peroxide, superoxide dismutase, and glutathione. It could be concluded that long-term treatment with CP confers a good antiinflammatory activity against arthritis in rat, leading to improvement of the oxidative stress induced by the arthritic insult. The reparative effect of the drug could be mediated via reduction of LTB(4) and IL-6.

Low dose carvedilol inhibits progression of heart failure in rats with dilated cardiomyopathy

The cardioprotective properties of carvedilol (a vasodilating beta-adrenoceptor blocking agent) were studied in a rat model of dilated cardiomyopathy induced by autoimmune myocarditis. Twenty-eight days after immunization, surviving Lewis rats (32/43=74%) were divided into three groups to be given 2 mg kg(-1) day(-1) (Group-C2, n=10) or 20 mg kg(-1) day(-1) (Group-C20, n=10) of carvedilol, or vehicle (0.5% methylcellulose, Group-V, n=12). After oral administration for 2 months, body weight, heart weight (HW), heart rate (HR), rat alpha-atrial natriuretic peptide (r-ANP) in blood, central venous pressure (CVP), mean blood pressure (mean BP), peak left ventricular pressure (LVP), left ventricular end-diastolic pressure (LVEDP), +/-dP dt(-1) and area of myocardial fibrosis were measured. Values were compared with those for normal Lewis rats (Group-N, n=10). Two out of 12 (17%) rats in Group-V died from day 28 to day 42 after immunization. No rat died in Groups-C2, -C20 and -N. Although the CVP, mean BP, LVP and +/-dP dt(-1) did not differ among the three groups, the HW, HR and r-ANP in Group-C2 (1.14+/-0.03, 339+/-16 and 135+/-31) and Group-C20 (1.23+/-0.04, 305+/-8 and 156+/-24) were significantly lower than those in Group-V (1.36+/-0.04 g, 389+/-9 beats min(-1) and 375+/-31 pg ml(-1), respectively). The LVEDP in Group-C2 was significantly lower than that in Group-V (7.4+/-1.4 and 12.2+/-1.2 mmHg, respectively, P<0. 05). The area of myocardial fibrosis in Group-C2 was smaller than that in Group-V (12+/-1 and 31+/-2%, P<0.01). These results indicate that a low dose of carvedilol has beneficial effects on dilated cardiomyopathy.

Are all beta blockers the same for heart failure?

Based on impressive morbidity and mortality data using beta blockers in heart failure, this therapy has now become part of the standard of care for patients with New York Heart Association II/III symptoms. The question remains whether there are clinically relevant differences between the beta blockers that have shown beneficial effects. This review summarizes the major mortality trials, and examines the smaller comparative trials of second and third generation beta blockers.

Oxidative stress in congestive heart failure

Heart failure is considered to be a complex clinical syndrome, with alterations in the multiple neurohumoral systems and subcellular cardiac sites that correlate with abnormal cardiac function. Strong evidence for the role of oxidative stress in the pathogenesis of heart failure has been provided by studies on experimental animals as well as humans. This concept is gaining more acceptance due to the fact that during heart failure, changes in different neurohormones, cytokines, nitric oxide, and activated inflammatory cells are closely linked to oxidative stress at the cellular and molecular levels. The present article provides a simple description of oxygen free radicals as well as the antioxidant defense system. Evidence for the role of oxidative stress in the pathogenesis of heart failure is reviewed in a concise manner.

Inhibitory effects of angiotensin-converting enzyme (ACE) inhibitors on oxygen radicals produced by bronchoalveolar lavage cells in young and aged guinea pigs

We examined the effect of angiotensin-converting enzyme (ACE) inhibitors and age on oxygen radical formation by bronchoalveolar lavage (BAL) cells. Lung-free cells, including pulmonary alveolar macrophages, were harvested from young (4-month-old) and aged (28-month-old) male guinea pigs using BAL. The oxygen radicals produced by BAL cells were measured by a lucigenin-dependent chemiluminescence method using a photon counter. Although spontaneous oxygen radical production by BAL cells from young and aged guinea pigs did not differ, the oxygen radical generation after maximal stimulation with phorbol-myristate acetate (PMA) was greater than that produced without PMA stimulation in both young and aged animals. ACE inhibitors with and without an SH-group (alacepril and lisinopril, respectively) were tested for their effect on oxygen radical formation by BAL cells; both ACE inhibitors inhibited oxygen radical production and generation by BAL cells from both young and aged guinea pigs in a dose-dependent manner. However, the alacepril concentration giving 50% inhibition (IC50) of oxygen radical generation by BAL cells was smaller than the IC50 of lisinopril in both young and aged guinea pigs. These results indicate that ACE inhibitors, in particular those with an SH-group, effectively reduce oxygen radical production by BAL cells from young and aged guinea pigs, and suggest that treatment with ACE inhibitors may be useful for ameliorating oxidant-associated pulmonary disorders in young and aged patients.

Gene expression of antioxidative enzymes in the human heart: increased expression of catalase in the end-stage failing heart

BACKGROUND

An increase in oxidative stress is suggested to be intimately involved in the pathogenesis of heart failure. However, gene expression of enzymes that metabolize reactive oxygen metabolites has not been investigated in the human heart.

METHODS AND RESULTS

Myocardial tissue homogenates of the left ventricular wall from hearts in end-stage failure due to dilated (DCM) or ischemic (ICM) cardiomyopathy (n=12 each), as well as from nonfailing donor hearts (n=12), were analyzed for mRNA levels of manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), glutathione peroxidase (GPX), and catalase by Northern blot analyses. Protein levels of MnSOD, CuZnSOD, and catalase were determined by Western blot or ELISA. MnSOD, CuZnSOD, and GPX mRNA levels were similar in all 3 groups. In contrast, catalase mRNA levels were found to be increased by 123+/-23% in DCM hearts and by 93+/-10% in ICM hearts (P<0.01 each) compared with control hearts. Likewise, catalase protein levels were found to be increased in failing hearts (DCM by 90+/-10%, ICM by 90+/-13%; P<0. 05 each) compared with control hearts. In addition, the observed upregulation of catalase mRNA and protein in failing hearts was attended by an increased catalase enzyme activity (DCM by 124+/-16%, ICM by 117+/-15%; P<0.01 each), whereas MnSOD, CuZnSOD, and GPX enzyme activity levels were unchanged in failing compared with nonfailing myocardium.

CONCLUSIONS

Increased oxidative stress in human end-stage heart failure may result in a specific upregulation of catalase gene expression as a compensatory mechanism, whereas SOD and GPX gene expression remain unaffected.

Effects of angiotensin-converting enzyme (ACE) inhibitors on oxygen radical production and generation by murine lung alveolar macrophages

We examined the effect of angiotensin-converting enzyme (ACE) inhibitors on oxygen radical production before and generation after phorbol-myristate acetate (PMA) stimulation of lung alveolar macrophages. Lung free cells, predominantly pulmonary alveolar macrophages, were obtained from Fischer 344 rats and guinea pigs using bronchoalveolar lavage. The oxygen radicals produced by pulmonary alveolar macrophages with or without stimulation of PMA were measured by lucigenin-dependent chemiluminescence method using a photon counter, Lumat 9501 (Berthold, Germany). Alacepril, an ACE inhibitor with SH-group, inhibited the oxygen radical production and generation by lung alveolar macrophages harvested from both rats and guinea pigs in a dose-dependent fashion. Approximately 0.3 mM of alacepril inhibited 50% of oxygen radical production of lung alveolar macrophages in both rats and guinea pigs, whereas a higher concentration (1-5 mM) of lisinopril, an ACE inhibitor without SH-group, was necessary to inhibit 50% of oxygen radical production of lung alveolar macrophages in the animals. These results suggest that an ACE inhibitor with SH-group acts as an antioxidant in murine lungs and the treatment with the ACE inhibitor may reduce oxidant stress in hypertensive patients with asthma.

beta-Blockers in congestive heart failure

Recent advances in the understanding of the basic mechanisms underlying congestive heart failure (CHF) have focused on the role of neurohormonal activation. Chronic adrenergic overstimulation is directly toxic to myocardial cells, impairs function, causes peripheral vasoconstriction and may induce programmed cell death via apoptosis. beta-Adrenergic blockade can interrupt this pathological process. Accumulating evidence now points to a clear role for beta-blocking agents in the management of heart failure, reducing both the morbidity and mortality associated with CHF. This report will review the recent clinical trials supporting the use of beta-blockers in CHF, briefly highlight some practical considerations in the use of these drugs in patients with CHF and discuss several areas of controversy in which further study is needed.

Metabolism of vitamin A in the heart increases after a myocardial infarction

The supply of vitamin A to the myocardium by storage organs during increased oxidative stress subsequent to myocardial infarction (MI) was examined in hemodynamically assessed rats using compartment analysis of a radio-labeled vitamin A. 3H-Vitamin A was injected into two groups of rats: an MI group and a control group. There were no differences in the plasma or myocardial content of total vitamin A (unlabeled + labeled) between the two groups. However, the proportion of 3H-vitamin A was greater in the myocardium as well as plasma of MI rats. Rats with MI also had significantly lower 3H-vitamin A levels in liver and kidney than sham controls. The greatest difference in vitamin A content was in the concentrations of 3H-labeled storage forms of vitamin A in the liver of MI animals. Activity of bile salt-dependent retinyl ester hydrolase, an enzyme responsible for hydrolyzing vitamin A storage forms, was significantly increased in the liver of MI animals. These data indicate that analysis of plasma concentrations of vitamin A to ascertain links to cardiac conditions may be inappropriate. Specifically, during MI, increased amounts of vitamin A are mobilized from the liver to the heart without changing plasma concentrations. This is facilitated by an increase in the activity of an enzyme that hydrolyzes vitamin A storage forms.