Systemic oxidative stress could predict assisted reproductive technique outcome.

PURPOSE: Previous studies have indicated that OxS (oxidative stress) may appear as a possible reason for poor ART outcome. Our aim was to study OxS levels in both partners of couples seeking Assisted reproduction Technology (ART). METHODS: Altogether 79 couples were recruited. Oxidative DNA damage (8-OHdG) and lipid peroxidation (8-EPI) were measured, and clinical background and ART outcomes were recorded. RESULTS: Both OxS markers accurately reflected clinical conditions with prominent negative effects attributable to genital tract infections, endometriosis, uterine myoma and smoking. Furthermore, the level of OxS was also affected by partner's state of health. The highest 8-EPI levels were detected in both partners when biochemically detectable pregnancies did not develop into clinically detectable pregnancies (in women, 97,8 ± 16,7 vs 72.9 ± 22,9, p = 0.007; in men, 89.6 ± 20,4 vs 72,1 ± 22,6, p = 0.049). CONCLUSIONS: To conclude, high grade systemix OxS in both partners may negatively affect the maintenance and outcome of pregnancy. Applying the detection of OxS in ART patients may select patients with higher success rate and/or those who require antioxidant therapy. This would lead to improvement of ART outcome as well as natural fertility.

Increased levels of hydrogen peroxide and nitric oxide in male partners of infertile couples.

We investigated the prevalence of oxidative stress in male partners of infertile couples displaying different inflammation patterns in their genital tract and/or oligospermia. The levels of acknowledged oxidative stress markers (8-isoprostanes [8-EPI], diene conjugates, reactive oxygen species-total antioxidant capacity [ROS-TAC] score) were elevated in both leukocytospermic men and subjects whose inflammation was limited only to expressed prostatic secretion and/or post-massage urine. Oligospermic men with severe inflammation were different from oligospermic men who had no inflammation at all - the former had elevated 8-EPI, diene conjugates and ROS-TAC score when compared to the latter indicating that inflammation has substantially more significant impact on oxidative stress markers than oligospermia status. At the same time nitric oxide (NO) and hydrogen peroxide (H2 O2 ) levels were significantly increased not only in the men with severe inflammation but also in men with borderline inflammation in their genital tact and in men having non-inflammatory oligospermia. NO, H2 O2 and 8-EPI were negatively correlated with per cent of normal sperms, and NO and H2 O2 showed negative correlation also with sperm count. We can conclude that in men presenting with couple infertility the acknowledged oxidative stress markers are substantially associated with markers of inflammation in genital tract while NO and H2 O2 display high levels also in patients with mild inflammation and non-inflammatory oligospermia.

Sexual intercourse with leukocytospermic men may be a possible booster of oxidative stress in female partners of infertile couples.

Human semen has undoubtedly significant influence on the organism of the female counterpart. At the same time there are no studies in English literature investigating the influence of sexual intercourse on oxidative stress level in women's organism. Seventeen infertile couples where male partners were with (n = 5) or without (n = 12) leukocytospermia were enrolled in the study. Systemic oxidative stress levels were measured, whereby twice in female partners - before and 8-12 h after sexual intercourse. The men with leukocytospermia were characterized by oxidative stress that was substantially transferred to their partners during sexual intercourse as revealed by increase in 8-isoprostanes level (median 32.7 vs. 70.4 ng/mmol creatinine, p = 0.006). Sexual intercourse with male partner having leukocytospermia increases the oxidative stress level in the women's organism that may interfere with fertilization.

Complete glutathione system in probiotic Lactobacillus fermentum ME-3.

There is much information about glutathione (GSH) in eukaryotic cells, but relatively little is known about GSH in prokaryotes. Without GSH and glutathione redox cycle lactic acid bacteria (LAB) cannot protect themselves against reactive oxygen species. Previously we have shown the presence of GSH in Lactobacillus fermentum ME-3 (DSM14241). Results of this study show that probiotic L. fermentum ME-3 contains both glutathione peroxidase and glutathione reductase. We also present that L. fermentum ME-3 can transport GSH from environment and synthesize GSH. This means that it is characterized by a complete glutathione system: synthesis, uptake and redox turnover ability that makes L. fermentum ME-3 a perfect protector against oxidative stress. To our best knowledge studies on existence of the complete glutathione system in probiotic LAB strains are still absent and glutathione synthesis in them has not been demonstrated.

Effects of a synbiotic product on blood antioxidative activity in subjects colonized with Helicobacter pylori.

AIM: To evaluate the impact of the consumption of a synbiotic product on the antioxidative activity markers of blood in asymptomatic H. pylori-colonized persons. METHODS AND RESULTS: Fifty-three healthy adult volunteers without gastric symptoms participated in a randomized, double-blind placebo-controlled study. The crossover consumption of the enterocoated capsules containing antioxidative Lactobacillusfermentum ME-3, Lact. paracasei 8700:2 and Bifidobacterium longum 46 with Raftilose P95 lasted for 3 weeks and did not change the H. pylori colonization. In H. pylori-positive subjects the sera values of total antioxidative status (TAS) were significantly lower compared to H. pylori-negative subjects (0.97 vs 1.05 mmol l(-1), P = 0.008). After the consumption of the synbiotic, TAS values (0.97 vs 1.03 mmol l(-1), P = 0.004) increased, while the ratio between oxidized and reduced glutathione (0.035 vs 0.030, P = 0.016) decreased in H. pylori-positive subjects. CONCLUSIONS: The consumption of a synbiotic containing an antioxidative probiotic strain improved the reduced systemic antioxidative activity in H. pylori-colonized asymptomatic subjects. SIGNIFICANCE AND IMPACT OF THE STUDY: A synbiotic product containing an antioxidative probiotic strain may be useful in the reduction of systemic oxidative stress in H. pylori infection.

Oxidative stress in leucocytospermic prostatitis patients: preliminary results.

The aim of this study was to contribute to the knowledge concerning pathogenesis of inflammatory chronic prostatitis by revealing possible shifts in the balance of markers of oxidative stress and anti-oxidative activity in case of leucocytospermic prostatitis. We also attempted to identify possible relations between seminal micro-organisms and oxidative stress parameters. A many-sided complex of local (spermatozoa, seminal plasma) and general (blood, urine) markers in 21 prostatitis patients and nine controls was compared. In both spermatozoa and seminal plasma, the content of diene conjugates was significantly higher in prostatitis patients compared with healthy controls. At the same time total anti-oxidative status in spermatozoa and total anti-oxidative activity in seminal plasma were lower in prostatitis patients than in controls. In urine, the level of 8-isoprostanes was significantly higher in prostatitis patients than in healthy controls, correlating well with 8-hydroxy-2'-deoxyguanosine. The latter correlated with cellular Fe and Ni contents as well, confirming that these metals with varying valency may cause DNA damage. Reduced glutathione showed higher levels in blood of controls than in prostatitis patients. Coryneform bacteria appeared to be associated with prostatitis-related oxidative stress. In conclusion, leucocytospermic prostatitis patients are characterised by oxidative stress at all levels: systemic (general), seminal plasma and cellular.

Homocysteine status in former top-level male athletes: possible effect of physical activity and physical fitness.

The importance of elevated homocysteine (Hcy) as a risk marker for cardiovascular disease is continuously under debate. Lifestyle factors may increase the total Hcy (tHcy) level of the plasma, but there are no consistent findings relating to Hcy, physical activity, and cardiorespiratory fitness. Cross-sectional measurement from an ongoing follow-up study was performed on 77 former male athletes and 33 sedentary controls (age range 35-62 years). Lifestyle parameters (current physical activity patterns, smoking, etc.), anthropometric and blood pressure data, and data about tHcy, reduced, and oxidized glutathione (GSH, GSSG, respectively) in blood, lipoproteins, and maximal oxygen consumption (VO(2max)) were collected. Our study results showed that the subgroup of physically active ex-athletes (n=52) had a significantly lower tHcy level and glutathione redox ratio (GSSG:GSH) in comparison with the subgroup of sedentary ex-athletes (n=25). tHcy level was inversely related to cardiorespiratory fitness (VO(2max)/kg). Dietary and smoking habits were not significantly associated with the tHcy level in our study group. In conclusion, the research findings indicate that both current physical activity and cardiorespiratory fitness are significantly inversely associated with an elevated homocysteine level in middle-aged former athletes.

Antagonistic activity of probiotic lactobacilli and bifidobacteria against entero- and uropathogens.

AIM: To develop in vitro assays for comparing the antagonistic properties and anti-oxidative activity of probiotic Lactobacillus and Bifidobacterium strains against various entero- and urinary pathogens. METHODS AND RESULTS: The antagonistic activity of five probiotic lactobacilli (Lactobacillus rhamnosus GG, Lactobacillus fermentum ME-3, Lactobacillus acidophilus La5, Lactobacillus plantarum 299v and Lactobacillus paracasei 8700:2) and two bifidobacteria (Bifidobacterium lactis Bb12, Bifidobacterium longum 46) against six target pathogens was estimated using different assays (solid and liquid media, anaerobic and microaerobic cultivation) and ranked (low, intermediate and high). Bacterial fermentation products were determined by gas chromatography, and the total anti-oxidative activity of probiotics was measured using linolenic acid test. Pyelonephritic Escherichia coli was highly suppressed by GG and both bifidobacteria strains. Lactobacilli strains 8700:2, 299v and ME-3 were the most effective against Salmonella enterica ssp. enterica in microaerobic while ME-3 and both bifidobacteria expressed high activity against Shigella sonnei in anaerobic milieu. Lact. paracasei, Lact. rhamnosus and Lact. plantarum strains showed intermediate antagonistic activity against Helicobacter pylori under microaerobic conditions on solid media. The highest anti-oxidative activity was characteristic for Lact. fermentum ME-3 (P < 0.05). No efficient antagonist against Clostridium difficile was found. The positive correlations between the pH, lactic acid production and anti-microbial activity for all tested probiotics were assessed. CONCLUSIONS: Developed experimental assays enable to compare the anti-microbial and -oxidative activity of Lactobacillus and/or Bifidobacterium probiotics, which have been claimed to possess the ability of suppressing the growth of various enteric and urinary pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Screening Lactobacillus and Bifidobacterium sp. strains according to their activity in various environmental conditions could precede the clinical efficacy studies for adjunct treatment with probiotics in cure of different gastrointestinal and urinary tract infections.

Atherogenic inflammatory and oxidative stress markers in relation to overweight values in male former athletes.

OBJECTIVE: To evaluate inflammation- and oxidative stress-related (OxS) background in former athletes in relation to overweight and abdominal obesity status. DESIGN: Cross-sectional data from ongoing follow-up study. SUBJECTS: A total of 60 middle-aged former athletes (46.6+/-7.5 years; 181.1+/-7.2 cm; 88.1 +/- 12.9 kg) and 54 age-matched controls (48.1+/-7.3 years; 181.4 +/- 6.2 cm; 89.7 +/- 14.4 kg). MEASUREMENTS: Anthropometric characteristics, serum lipoproteins (CHOL, HDL-C, LDL-C, TG), oxidized LDL (oxLDL), diene conjugates (DC) and high-sensitive C-reactive protein (hsCRP). Information about the physical activity and other lifestyle variables were collected by the questionnaire. RESULTS: Ex-athletes were characterized by significantly higher physical activity characteristics and lower CHOL and oxLDL in comparison with controls. Correlation analysis among ex-athletes revealed negative associations between all measured overweight data (body mass index, fat percentage, waist to hip circumferences and waist circumference (WC)), and current physical activity. Current physical activity was significantly related to OxS and inflammatory characteristics (oxLDL, DC and hsCRP) among the ex-athletes, but not among the control group. The most expressed positive correlations were found between WC, hsCRP, triglycerides (TG), DC and oxLDL in both study groups. CONCLUSION: Our study results suggest that there exists an independent (adjusted for potential confounders) association between overweight, abdominal obesity, and atherogenic inflammatory and oxidative stress markers in ex-athletes as well as in age-matched controls. Major findings of our study show that WC is the best correlate of hsCRP, oxLDL, DC and TG levels.

An antioxidant tetrapeptide UPF1 in rats has a neuroprotective effect in transient global brain ischemia.

Different glutathione analogues have potential to maintain or increase tissue glutathione level and to scavenge the reactive oxygen species. We designed and synthesized a novel non-toxic glutathione analogue, named UPF1, which possessed 60-fold higher hydroxyl radical scavenger efficiency in vitro, compared with glutathione itself, and investigated the effects of UPF1 on a four-vessel occlusion model of rats. The UPF1 was administered via the jugular vein in two separate experiments at two time points: 20 min before global brain ischemia and immediately before reperfusion. In both cases the number of pyramidal cells surviving in the subfield of CA1 at the dorsal hippocampus in the UPF1-treated groups of rats was twice as high as in the vehicle group.

A new probiotic cheese with antioxidative and antimicrobial activity.

The aim of our study was to develop an original probiotic cheese based on the Estonian open-texture, smear-ripened, semisoft cheese "Pikantne." Cheese was produced by two methods using cheese starter cultures (Probat 505) in combination with 0.04% of probiotic Lactobacillus fermentum strain ME-3 (10(9) cfu/mL) with high antimicrobial activity and antioxidative properties. The probiotic Lactobacillus was added into milk simultaneously with starter cultures (cheese A) and into drained curd (cheese B). After addition of probiotic L. fermentum ME-3, the cheese composition, flavor, and aroma were comparable to the control cheese (score values = 4.5, 4.2, and 3.7 for control cheese, cheese A, and cheese B, respectively). Cheese A, which had good sensory properties, was chosen for further testing of viability and probiotic properties. The probiotic strain was found to withstand the technological processing of cheese, surviving and sustaining moderate antimicrobial and high antioxidative activity throughout ripening and storage (the ripened cheese contained approximately 5 x 10(7) cfu/g viable ME-3 cells), although the viability of the ME-3 strain incorporated into the cheese showed a slight decrease between d 24 and 54 after cheese preparation. Semisoft cheese "Pikantne" serves as a suitable carrier of antimicrobial and antioxidative L. fermentum ME-3.

High-sensitive C-reactive protein level and oxidative stress-related status in former athletes in relation to traditional cardiovascular risk factors.

OBJECTIVE: To analyze systemic and cellular oxidative stress-related indices as well as C-reactive protein level in former top-level athletes in relation to traditional cardiovascular risk factors. METHODS: A cross-sectional study was performed in 53 former male athletes and 25 sedentary controls (age range: 39-59 years). We measured anthropometric factors (BMI, fat percentage, WHR), resting blood pressure (SBP, DBP), serum cholesterol (CHOL), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), total antioxidant status (TAS), oxidized LDL-C (oxLDL), diene conjugates (DC), glutathione redox status, high-sensitive C-reactive protein (hsCRP), and leisure-time physical activity. RESULTS: Physically active former athletes had significantly lower mean overweight (BMI, fat percentage, WHR), better spectrum of atherogenesis indicators (CHOL, HDL-C, TG, TG:HDL-C ratio) and lower oxidative stress (oxLDL, oxLDL:LDL-C ratio, DC) values than sedentary ex-athletes. No significant differences in these variables were found between the sedentary ex-athletes and control group. Significant associations were found between physical activity (METs), SBP, DBP, hypertension, CHOL, HDL-C, TG, TG:HDL-C ratio, oxLDL, oxLDL:LDL-C ratio, DC and hsCRP. CONCLUSIONS: A physically active lifestyle is related to a lower cardiovascular disease (CVD) risk profile including a substantially lower systemic and cellular oxidative stress status as well as C-reactive protein level in middle-aged men.

Is elective abdominal aortic aneurysm repair accompanied by high grade oxidative stress?

BACKGROUND AND AIMS: During elective abdominal aortic aneurysm repair (AAAR), lower torso ischaemia-reperfusion event is unavoidable. Previous studies on AAAR have reported the importance of oxidative stress (OS) in ischaemia-reperfusion injury, however, the grade of OS has not been adequately clarified up to now. The aim of this study was to perform a complex investigation of the time-course and grade of systemic and cellular OS in patients undergoing AAAR. MATERIAL AND METHODS: Arterial blood samples were taken from 18 patients undergoing elective AAAR (at four points in time: before anaesthesia, 5 min after aortic clamping and 5 min and 30 min after clamp removal). Diene conjugates (DC), thiobarbituric acid reactive substances (TBARS), total antioxidative capacity (TAC), glutathione redox ratio (GSSG/GSH), and levels of antioxidative enzymes as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) were measured from the radial arterial blood. RESULTS: 30 min after the removal of the aortic cross-clamp, arterial CAT showed significant elevation (96.0 vs 56.9 U/l, p < 0.05); GSHPx was significantly elevated (51.5 vs 39.9 U/g Hgb, p < 0.05) and TAC was decreased (31.4 vs 36.5%, p < 0.05) in comparison with preoperative value. CONCLUSIONS: We found limited alterations of several OS parameters, which do not characterize either systemic or cellular high-grade OS during elective AAAR.

Characterization of intestinal lactobacilli as putative probiotic candidates.

AIMS: To use antioxidative activity and antagonistic properties of lactobacilli against selected pathogens and members of the normal microflora as a basis for screening probiotic candidates. METHODS AND RESULTS: Antagonistic activity of lactobacilli against target bacteria in both microaerobic and anaerobic environments was tested. Production of antagonistic metabolites (ethanol, hydrogen peroxide (H2O2), acetic, lactic and succinic acid) by lactobacilli as well as their total antioxidative activity were assessed. In general, the lactobacilli tested were most effective against Gram-negative bacteria and their antagonistic activity was strain-specific. However, obligately heterofermentative lactobacilli had the strongest activity when tested in a microaerobic environment. Additionally, facultatively heterofermentative lactobacilli were equally effective in either milieu and produced significant levels of acetic and lactic acid. Moreover, obligately homofermentative lactobacilli had high H2O2 production and total antioxidative activity but weak antagonistic activity. CONCLUSIONS: Antioxidative and antagonistic activity of intestinal lactobacilli is strain-specific but typically can be related to their fermentation type which may be used for rapidly screening large numbers of lactobacilli for probiotic candidates. SIGNIFICANCE AND IMPACT OF THE STUDY: This study represents the first report on the utilization of group characteristics to screen lactobacilli intended for specific probiotic use. Such uses include the targeting of particular gut niches and pathogens as well as allowing for long-term benefits to the host.

[Changes of parameters of the functional state of the organism and oxidative stress in patients after surgical revascularization at early stage of restorative treatment]. / Izmeneniia pokazatelei funktsional'nogo sostoianiia organizma i oksidativnogo stressa u bol'nykh posle khirurgicheskoi revaskuliarizatsii miokarda na rannei stadii vosstanovitel'nogo lecheniia.

Early complex restorative treatment with individualized aerobic physical exercise in 2-4 weeks after surgical myocardial revascularization significantly increased physical working capacity and cardiorespiratory reserve of the body. Pronounced oxidative stress which had been present after myocardial revascularization decreased under the action of restorative therapy. Most pronounced increases of total physical capacity and cardiorespiratory reserve and lowering of oxidative stress occurred in patients with lowest initial parameters of the functional state of the organism.

The cerebrocortical areas in normal brain aging and in Alzheimer's disease: noticeable differences in the lipid peroxidation level and in antioxidant defense.

The markers of oxidative stress were measured in four cerebrocortical regions of Alzheimer's disease (AD) and age-matched control brains. In controls the levels of diene conjugates (DC) and lipid peroxides (LOOH) were significantly higher in the sensory postcentral and occipital primary cortex than in the temporal inferior or frontal inferior cortex. The antioxidant capacity (AOC) was highest in the temporal, and GSH in the frontal inferior cortex. The highest activity of superoxide dismutase (SOD) and catalase (CAT) was found in the occipital primary cortex. Compared with controls, significantly higher level of DC and LOOH and attenuated AOC were evident in AD temporal inferior cortex. In AD frontal inferior cortex moderate increase in LOOH was associated with positive correlation between SOD activity and counts of senile plaques. Our data suggest that in AD cerebral cortex, the oxidative stress is expressed in the reducing sequence: temporal inferior cortex > frontal inferior cortex > sensory postcentral cortex approximately = occipital primary cortex, corresponding to the histopathological spreading of AD from the associative to primary cortical areas.

Patients with allergic and irritant contact dermatitis are characterized by striking change of iron and oxidized glutathione status in nonlesional area of the skin.

To assess the consequences of oxidative stress in allergic and irritant contact dermatitis, we compared the iron level, unsaturated iron-binding capacity, total iron binding capacity, the percentage saturation of iron-binding capacity, the amount of diene conjugates as well as the amounts of total glutathione, reduced glutathione, oxidized glutathione, and the oxidized glutathione/reduced glutathione ratio in skin homogenate from lesional and nonlesional skin. Lesional skin samples were obtained from positive patch test sites to 5% NiSO4 in five subjects, and from chronic contact dermatitis lesions on the hands, which had exacerbated over 3--9 wk in six subjects. Contact dermatitis caused at least a 4-fold increase in the iron level in the lesional skin area compared with the nonlesional skin area (p < 0.02). The increase in the iron level depended on the duration of contact dermatitis and was accompanied by high unsaturated iron-binding capacity and total iron-binding capacity values in the positive patch test sites (p < 0.05), and by a high percentage saturation value in the chronic contact dermatitis lesions (p < 0.05). We found high indices for iron, total iron-binding capacity and diene conjugates in the apparently healthy skin of the patients with persistent contact dermatitis that significantly (p < 0.05) exceeded the corresponding values in the patients with only patch test reactions. In summary, we have succeeded in providing evidence that generalized oxidative damage of the skin occurs as a consequence of contact dermatitis in a restricted area.

Acute immune response in respect to exercise-induced oxidative stress.

The relationship between exhaustive exercise, oxidative stress, the protective capacity of the antioxidant defense system and cellular immune response has been determined. Exhaustive exercise in well-trained young men (n=19)-induced leukocytosis, decreased proportion of activated-lymphocyte subsets (CD4+ and CD8+) expressing CD69, decreased lymphocyte mitogenic response to concanavalin A (ConA) and phytohemagglutinin (PHA), increased lipid peroxidation, increased total antioxidant status (TAS) and catalase activity, immediately after exercise. Suppressed blood concentration of T-lymphocyte subsets (CD3+, CD4+, CD8+, NK), increased TAS and blood total glutathione (TGSH) in early recovery period (30 min after exercise) were found. Strong positive correlation was observed between TGSH and lymphocyte mitogenic response to ConA and PHA (r=0.85 and 0.85, respectively) immediately after exercise. Moderate positive correlation was observed between TAS and lymphocyte mitogenic response to PHA (r=0.59) immediately after exercise as well as between TAS and lymphocyte mitogenic response to PHA and ConA (r=0.69 and 0.54, respectively). Moderate to weak correlation was observed between TAS and conjugated dienes with exercise (r=0.66) as well as in 30-min recovery (r=0.50). After a short-term bout of exhaustive exercise, immune system was characterized by acute phase response, which was accompanied with oxidative stress. Suppression of the cellular immunity 30 min after exercise shows that this period is not enough for recovery after exhaustive exercise. The results suggest the interactions between exercise-induced oxidative stress and immune response.

Effect of low-dose aspirin on the markers of oxidative stress.

UNLABELLED: The present study estimates effects of low-dose enteric coated aspirin (ECA) on oxidative stress (OS) markers in a group of middle-aged men (mean age 51.2 +/- 6.9 years) free of pre-existing ischemic heart disease. METHODS: Serum products of lipid peroxidation, and measures of antioxidative status were detected in 25 healthy men in baseline and after two-week treatment period. RESULTS: In respect to serum products of lipid peroxidation and markers of antioxidant status, no statistically significant differences between the pre- and after-treatment data were observed for any measures, with the exception of values of serum antioxidative capacity (39.0 +/- 2.5 and 42 +/- 4.6, respectively). CONCLUSIONS: Administration of ECA does not initiate the OS in blood and improves the general antioxidative potency of blood. This may imply towards certain antiatherogenic influence of low-dose ECA, exhibited even with a short-term treatment period. Regarding OS markers, a variety of individual responses observed in the selected subgroups should be investigated and possibly taken into account while treatment with ECA is initiated for primary prevention of cerebrovascular events.

Preconditioning with hydrogen peroxide (H2O2) or ischemia in H2O2-induced cardiac dysfunction.

The possible cardioprotective effects of preconditioning by ischaemia (IPC) or a low dose of H2O2 (HPC) prior to a high dose of H2O2 was investigated. Langendorff-perfused rat hearts (n = 10 in each group) were subjected to 10 min of 140 micromol/L H2O2 and 30 min recovery after either (1) control perfusion, (2) 20 micromol/L H2O2 for 10 min, recovery 10 min, or (3) 2 x 2 min global ischaemia and 5 min reperfusion. 140 micromol/L H2O2 increased left ventricular end-diastolic pressure from 0 to 68+/-8 mmHg in controls (mean+/-SEM), which was attenuated by IPC (46+/-9 mmHg, p<0.001) and HPC (18+/-4 mmHg, p < 0.001 compared to controls, p < 0.01 compared to IPC). HPC, but not IPC, improved coronary flow (p < 0.02) and left ventricular developed pressure (p < 0.001) during recovery. Troponin T release was similar in all groups. Tissue thiobarbituric acid reactive substances, antioxidant capacity, catalase, and glutathione peroxidase were not influenced by 140 micromol/L H2O2. H2O2 decreased the level of tissue glutathione. This reduction was augmented by HPC (p <0.02) and attenuated by IPC (p < 0.02). H2O2 increased superoxide dismutase (p < 0.04). The increase was attenuated by IPC (p < 0.05), but not influenced by HPC. HPC efficiently protected cardiac function in H2O2-induced cardiac injury, while IPC had only a small protective effect. The functional protection cannot be explained by reduction of irreversible injury, attenuation of lipid peroxidation, or modification of tissue antioxidant parameters.