The short-term effects of soybean intake on oxidative and carbonyl stress in men and women.

Beyond other beneficial effects, a soy-rich diet has been shown to reduce the risk of cardiovascular diseases and diabetic complications. Reduction of oxidative and carbonyl stress has been proposed as the underlying mechanism, but the evidence for this is lacking. The aim of our study was to evaluate the effects of short-term increased soy intake on oxidative and carbonyl stress parameters in young volunteers. Young healthy probands (omnivores) of both genders (55 women, 33 men) were given soybeans (2 g/kg bodyweight daily) for one week. Markers of oxidative and carbonyl stress were measured in plasma at the beginning and at the end of one week soybean intake and after another week of a wash-out period. Total antioxidant capacity was increased by soybean intake in both genders. This led to decreased levels of advanced oxidation protein products in women, but not in men. On the contrary, in men, soybean intake increased lipoperoxidation. No effects on carbonyl stress markers (advanced glycation end products-specific fluorescence and fructosamine) were found. Soybean intake has gender-specific effects on oxidative stress in young healthy probands potentially due to divergent action and metabolism of phytoestrogens in men and women. Effects of soybean intake on carbonyl stress should be evaluated in longer studies.

Advanced glycation end products in myocardial reperfusion injury.

Advanced glycation end products (AGEs) are associated with cardiovascular diseases. Whether the AGE levels change during myocardial reperfusion injury is currently unknown. The aim of our study was to investigate the dynamics of AGEs in myocardial reperfusion injury and to discuss potential reasons for these changes. The dynamics of AGEs, pentosidine and neopterin in the plasma of patients with acute myocardial infarction (AMI) treated using thrombolysis (n = 40) were analyzed. In addition, AGEs were measured in patients with open heart surgery (n = 12) and rabbits with induced AMI (n = 9). In all three studies of myocardial reperfusion injury, a significant decrease of AGEs was observed (by 26 ± 19% in patients with AMI, by 23 ± 14% in patients with open heart surgery and by 39 ± 10% in rabbits with AMI within 1 day of reperfusion; p < 0.05 in all studies). In additional studies, an association between lower AGEs and an activated immune system (R (2) = 0.09; p < 0.01) and fasting (decrease by 38%; p < 0.01) was shown. AGEs decrease in reperfusion injury of the heart. Indices pointing towards the involvement of immune system activation and fasting are presented. Further studies focusing on the underlying mechanism and on the clinical value of the observed dynamics of AGEs are needed.

Oxidative and carbonyl stress in patients with obstructive sleep apnea treated with continuous positive airway pressure.

PURPOSE: The pathogenesis of cardiovascular complications of obstructive sleep apnea syndrome (OSAS) can be explained by oxidative and carbonyl stress due to oxygenation and reoxygenation injury during sleep. This hypothesis has yet to be proved experimentally, although several clinical observations have found increased oxidative damage in plasma. Continuous positive airway pressure (CPAP) improves symptoms and prognosis of patients with OSAS. METHODS: Patients with confirmed SAS (n = 89) underwent polysomnography and received CPAP treatment. Plasma and saliva samples were taken before CPAP therapy as well as after 1 and 6 months of CPAP treatment. Selected markers of oxidative and carbonyl stress were measured in plasma and saliva, and their dynamics was statistically analyzed. RESULTS: Plasma levels of thiobarbituric acid reacting substances-a marker of lipoperoxidation-and advanced glycation end products (AGEs)-a marker of carbonyl stress-were decreased by the CPAP therapy. The decrease of AGEs and fructosamine was also found in saliva. Interestingly, no gender differences and no changes of antioxidant status measured as total antioxidant capacity and ferrous reducing ability were found in either of the samples. CONCLUSION: Previous findings of lowered plasma markers of oxidative stress were confirmed. Plasma AGEs were lowered by CPAP therapy. This is the first study analyzing markers of oxidative and carbonyl stress in saliva. Non-invasive sampling of saliva makes it a very interesting source of information for repeated monitoring of therapy success. Salivary AGEs and fructosamine as markers of carbonyl stress were decreased by the CPAP therapy and might therefore have potential informative value for clinical observations, as well as for the understanding of the pathogenesis of OSAS complications.

Variability of thiobarbituric acid reacting substances in saliva.

INTRODUCTION: Salivary TBARS are a potential marker of oxidative stress in the oral cavity. Previous studies have found increased levels of salivary TBARS in various diseases. The aim of this study was to assess the variability of salivary TBARS in both genders. SUBJECTS & METHODS: Saliva samples from thirty-eight healthy volunteers (18F & 20M) were collected every day during 30 day period. TBARS levels were measured spectrophotometrically using a high-throughput 96-well plate method. Time series analysis was performed using standard statistical methods. RESULTS: Repeated measures ANOVA showed a significant variation of salivary TBARS within day and subjects (p < 0.001). The dynamics did not differ between genders. Intraindividual variability was very high in both genders with coefficients of variation of more than 60%. Interindividual variability was higher in men than in women (73% vs. 46%; p < 0.01). DISCUSSION: The relatively high intraindividual variability indicates that the use of salivary TBARS will be limited to research on a population level, although some informative value might be gained by repeated samplings. Factors influencing the biological variability of salivary TBARS should be identified in further studies.

Salivary thiobarbituric acid reacting substances and malondialdehyde--their relationship to reported smoking and to parodontal status described by the papillary bleeding index.

BACKGROUND: Thiobarbituric reacting substances (TBARS) are markers of lipoperoxidation. The best-known specific TBARS is malondialdehyde (MDA). Results from our previous studies have shown that TBARS can be measured in saliva and are increased in patients with gingivitis. Whether MDA is the main TBARS in saliva from patients with altered parodontal status is unknown. Aim. To observe the relationship between the parodontal status and TBARS, MDA and the number of epithelial cells in saliva. SUBJECTS & METHODS: In Study I saliva and plasma samples of 15 patients (8F, 7M) suffering from inflammatory periodontal diseases were gathered and TBARS levels were measured in these samples. In Study II saliva samples from 217 consecutive stomatologic patients were collected and analysed for TBARS spectrofluorometrically, MDA by high-performance liquid chromatography and epithelial cell count by light microscopy. Papillary bleeding index (PBI) was determined in standard stomatologic examination. RESULTS: In Study I results from our previous studies showing no correlation between salivary and plasma TBARS levels were confirmed. This indicates that the local salivary level of TBARS is unlikely to be directly affected by systemic oxidative stress. In Study II higher PBI was associated independently (adjusted for age and sex) tightly with higher TBARS (p<0.001) and with lower number of epithelial cells in saliva (p<0.05). Smokers had higher salivary MDA levels (p<0.003) and lower number of epithelial cells in saliva (p<0.01). CONCLUSION: Salivary TBARS are a simple parameter that partially reflects the parodontal status with a potential usefulness in the clinical stomatology. We show herein that salivary MDA is dependent on age and smoking, but there is no correlation between MDA and PBI. Further studies should uncover the main salivary TBARS compound in patients with altered parodontal status and trace the origin of these salivary lipoperoxidation markers.

Oxidative stress and antioxidant defense systems in patients after heart transplantation.

Heart transplantation ranks among those surgical interventions associated with ischemia-reperfusion injury to the donor heart as well as to the recipient. These events are connected with increased production of reactive oxygen species which evoke metabolic, structural and functional disturbances. Twenty-four transplant patients were investigated for oxidative stress (plasma levels of thiobarbituric acid reactive substances, TBARS) and antioxidant capacity (plasma total antioxidant status, TAS), and for activities of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx) during the first year after heart transplantation. The post-transplant period was characterized by progressive decrease of plasma TAS, indicating a significant long-term drop of antioxidant reserves in patients after successful heart transplantation. The decrease in plasma TAS is accompanied by long-lasting increase of TBARS levels, which may represent oxidative stress of the organism. We conclude that additional therapy with antioxidant substances should be an important component of the complex therapeutic programme of patients after heart transplantation.

Effects of anabolic steroids and antioxidant vitamins on ethanol-induced tissue injury.

Various mechanisms are involved in the process of ethanol-induced tissue impairment. Oxidative stress and its effects are among the most important. We compared the effects of antioxidant vitamins (vitamin C and E in combination) and steroids (testosterone and nandrolone separately) on the toxicity of ethanol in rats. Animals (male Wistar rats, n = 48) were randomised into following groups-Control, Ethanol, Testosterone, Ethanol + Testosterone, Ethanol + Nandrolone, Ethanol + Vitamins. Alcohol was given daily by gavage in a dose of 5 g/kg of body weight. On the 27th day of the study the animals were sacrificed by decapitation and tissue samples were taken. Metabolic status, parameters of the hepatic metabolism, hormone levels (testosterone, ACTH, corticosterone), lipoperoxidation markers (malondialdehyde and conjugated diens in forebrain cortex and in cerebellum) and advanced glycation end-products were analysed. Tissue samples underwent histological examination. Histological outcomes showed a protective effect of antioxidants on hepatic and cerebellar injury caused by chronic ethanol intake. Anabolic steroids protected especially the central nervous tissue against the toxicity of alcohol. Both, antioxidant vitamins and anabolic steroids protect against the ethanol-induced toxicity, however, this effect is tissue specific.