Simple and specific test for measuring lipid peroxides in plasma

Olmesartan Attenuates Single-Lung Ventilation Induced Lung Injury via Regulating Pulmonary Microbiota

Single-lung ventilation (SLV) associated acute lung injury is similar to ischemia reperfusion (IR) injury which is usually occurred during lung surgery. Olmesartan (Olm), a novel angiotensin receptor blocker (ARB), has been reported to ameliorate organ IR injury. Several recent studies have shown that lung microbiota may be involved in pulmonary diseases, but the effect of pulmonary microbiota in SLV-induced lung injury has not been reported. This study aims to determine the mechanism of how Olm attenuates SLV induced lung injury. Our data showed that 7 days Olm treatment before modeling markedly alleviated SLV-induced lung injury by suppressing inflammation and reactive oxygen species. Bronchoalveolar lavage fluid samples from the injured side were collected for 16S rRNA gene-based sequencing analysis and 53 different bacteria at the genus and species levels were identified. Furthermore, the injured lung samples were collected for metabolomics analysis using liquid chromatography-mass spectrometry analyses to explore differential metabolites. The Kyoto Encyclopedia of Genes and Genomes (KEGG) was applied to analyze the correlation between differential metabolites and lung microbiota. A total of 38 pathways were identified according to differential metabolites and 275 relevant pathways were enriched via analyzing the microbial community, 24 pathways were both identified by analyzing either metabolites or microbiota, including pyrimidine metabolism, purine metabolism, aminoacyl-tRNA biosynthesis and ATP-binding cassette transporter. Besides classical blockage of the renin-angiotensin II system, Olm could also alleviate SLV-induced lung injury by rewiring the interaction between pulmonary microbiota and metabolites.

Increased systemic and peritoneal oxidative stress biomarkers in endometriosis are not related to retrograde menstruation

Objetives: The goal of this study was to determine if systemic and peritoneal oxidative stress biomarkers are related to each other and to retrograde menstruation in endometriosis. Methods: Plasma and peritoneal fluid oxidative stress biomarkers and hemoglobin and erythrocytes in peritoneal fluid as retrograde menstruation indicators, were measured in 28 patients with endometriosis and 23 without endometriosis. Results: In the peritoneal fluid, carbonyls and lipohydroperoxides, indicative of protein and lipid oxidative damage, were higher in endometriosis group (21%, p = 0.016 and 46%, p = 0.009, respectively). However, these biomarkers were not different in the blood plasma of both groups, and only protein dityrosine, was increased in the plasma of endometriosis group (31%, p = 0.04). The peritoneal fluid hemoglobin content was not higher in the endometriosis group, nor related to carbonyls and lipohydroperoxides. Additionally, the peritoneal fluid oxidative biomarkers were not correlated with the blood plasma ones, and only malondialdehyde, and ischemia-modified albumin were almost two times higher in peritoneal fluid. Discussion: Our results show a peritoneal and systemic oxidative stress biomarkers increase in endometriosis, but not related to each other, and do not support the hypothesis of an increase in hemoglobin-iron supply towards the peritoneal cavity that causes oxidative damage.

Importance of internal mammary artery perfusion in cardiac ischemia and reperfusion

Purpose: Our purpose was to investigate the changes in antioxidant defense systems due to internal mammary artery (IMA) perfusion during coronary artery bypass graft (CABG) operations in which proximal anastomoses were completed under partial bypass with the aid of a side-biting clamp.

Material and Method: Twenty-five patients to be studied were divided into two groups according to the criterion of whether during proximal anastomoses left internal mammary artery (LIMA) perfusion was applied ( n = 15, LIMA group) or not ( n = 10, non-LIMA group). The erythrocyte catalase (CAT), superoxide dismutase (SOD), serum lipid peroxidation (LPO) products and whole blood reduced glutathione (GSH) levels were measured in the blood samples taken from the coronary sinus before cardiopulmonary bypass (CPB) (t1), before declamping (t2), at the 5th min after declamping (t3), at the 5th (t4) and 15th (t5) min after removing the side-biting clamp.

Results: While erythrocyte CAT enzyme activity decreases in both groups after the basal measurements, no significant difference was detected between the groups. Although the GSH levels did not differ at t1, t2 and t3, they were found to be higher in the LIMA group at t4 ( p = 0.006) and t5 ( p = 0.021). The erythrocyte SOD enzyme activity decreased after the basal measurements in both groups, but this reduction was less in the LIMA group at t4 ( p= 0.034) and t5 ( p = 0.018) compared to the other group. LPO products rose in both groups when reperfusion started after declamping. The levels of LPO products were significantly higher at t4 and t5 in the non-LIMA group than the other group ( p = 0.011 and p = 0.008).

Conclusion: If proximal anastomoses of coronary grafts are completed under partial bypass, permitting LIMA perfusion during this procedure will be beneficial to antioxidant defense systems.

Low volume-high intensity interval exercise elicits antioxidant and anti-inflammatory effects in humans

The purpose of the present study was to compare acute changes in oxidative stress and inflammation in response to steady state and low volume, high intensity interval exercise (LV-HIIE). Untrained healthy males (n = 10, mean ± s: age 22 ± 3 years; VO2MAX 42.7 ± 5.0 ml · kg(-1) · min(-1)) undertook three exercise bouts: a bout of LV-HIIE (10 × 1 min 90% VO2MAX intervals) and two energy-matched steady-state cycling bouts at a moderate (60% VO2MAX; 27 min, MOD) and high (80% VO2MAX; 20 min, HIGH) intensity on separate days. Markers of oxidative stress, inflammation and physiological stress were assessed before, at the end of exercise and 30 min post-exercise (post+30). At the end of all exercise bouts, significant changes in lipid hydroperoxides (LOOH) and protein carbonyls (PCs) (LOOH (nM): MOD +0.36; HIGH +3.09; LV-HIIE +5.51 and PC (nmol · mg(-1) protein): MOD -0.24; HIGH -0.11; LV-HIIE -0.37) were observed. Total antioxidant capacity (TAC) increased post+30, relative to the end of all exercise bouts (TAC (µM): MOD +189; HIGH +135; LV-HIIE +102). Interleukin (IL)-6 and IL-10 increased post+30 in HIGH and LV-HIIE only (P < 0.05). HIGH caused the greatest lymphocytosis, adrenaline and cardiovascular response (P < 0.05). At a reduced energy cost and physiological stress, LV-HIIE elicited similar cytokine and oxidative stress responses to HIGH.

Acute phase response and oxidative stress status in familial Mediterranean fever (FMF)

We aimed to determine acute phase response (APR) and oxidative stress in patients with familial Mediterranean fever (FMF) and compare these characteristics with those in healthy controls; 20 patients with FMF and 15 healthy controls were enrolled in the study. The erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), fibrinogen, and leukocyte levels were determined as markers of APR. Thiobarbituric acid reactive substances (TBARS), conjugated diene, and lipid hydroperoxide levels were measured as markers of lipid peroxidation. Carbonyl group and thiol (T-SH) levels were analyzed to determine the oxidative damage to proteins, and 8-hydroxy-2-deoxyguanosine (8-OHdG) was measured to reflect DNA oxidation. The erythrocyte glutathione (GSH) level, and glutathione peroxidase (GSH-Px), CuZn superoxide dismutase (CuZn SOD), and catalase activities were measured as markers of antioxidant status. Conjugated diene (p < 0.001) and carbonyl group (p < 0.05) levels were significantly higher and GSH-Px activity (p < 0.01) was significantly lower in FMF patients compared with controls. FMF patients in the attack period (n = 8) had significantly higher CRP, ESR, fibrinogen, and leukocyte levels (p < 0.001) than patients in the attack-free period (n = 12). The T-SH level (p < 0.05) was significantly higher and CuZn SOD activity was significantly lower (p < 0.05) in FMF patients in the attack period. The findings revealed upregulated APR during the attack period in FMF patients and enhanced oxidative stress in the FMF patients as compared to controls.

Effects of Urtica dioica on hepatic ischemia-reperfusion injury in rats

OBJECTIVES

To evaluate the effects of Urtica dioica on hepatic ischemia-reperfusion injury.

METHODS

Thirty adult male Wistar albino rats were divided into three groups: sham group (group 1), control group (group 2), and Urtica dioica group (group 3). All the rats were exposed to hepatic ischemia for 60 min, followed by 60 min of reperfusion. In group 2, a total of 2 ml/kg 0.9% saline solution was given intraperitoneally. In group 3, a total of 2 ml/kg Urtica dioica was given intraperitoneally. At the end of the procedure, liver tissue and blood samples were taken from all rats. Serum aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, ceruloplasmin, catalase, paraoxonase, arylesterase, and lipid hydroperoxide levels were measured. Liver tissue histopathologies were also evaluated by light microscopy.

RESULTS

Serum aspartate aminotransferase, alanine aminotransferase and lactate dehydrogenase levels were significantly higher in group 2 than in group 1, and significantly lower in group 3 than in group 2. Also, group 2 had higher serum lipid hydroperoxides and ceruloplasmin levels but lower catalase, paraoxonase, and arylesterase levels than group 1. In group 3, serum lipid hydroperoxides and ceruloplasmin levels were significantly lower, and catalase, paraoxonase, and arylesterase levels were higher than those in group 2. Histopathological examination showed that liver tissue damage was significantly decreased in group 3 compared with group 2.

CONCLUSIONS

Urtica dioica has a protective effect on the liver in hepatic ischemia-reperfusion-injured rats.

Effects of atorvastatin therapy on hypercholesterolemic rabbits with respect to oxidative stress, nitric oxide pathway and homocysteine

Hypercholesterolemia is characterized with changes in lipid profile, nitric oxide pathway and oxidative stress markers. This study is designed to evaluate the effects of hypercholesterolemic diet and atorvastatin therapy on oxidative stress, lipid peroxide and thiobarbituric acid reactive substances (TBARS), NO pathway markers, nitric oxide(NO) and asymmetric dimethylarginine (ADMA), homocysteine, and paraoxonase activity (PON1) in rabbits. Twenty rabbits fed with high-cholesterol diet for 8 weeks were randomly divided into 2 groups on the fourth week of the hypercholesterolemic diet. First group was fed with high-cholesterol diet alone, whereas the second group with the same cholesterol diet plus atorvastatin (0.3 mg/kg/day) for 4 weeks. High-cholesterol diet increased total cholesterol, low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), ADMA, TBARS and lipid peroxide levels and reduced PON1 activity and NO levels in rabbits. Four weeks of atorvastatin therapy significantly increased HDL-C, PON1 activity and reduced LDL-C, TBARS and lipid peroxide concentrations. Atorvastatin therapy is beneficial in decreasing oxidative stress related with hypercholesterolemia, mainly affecting lipid profile and PON1 activity.

Decreased Total Antioxidant Response and Increased Oxidative Stress in Behcet's Disease

Behcet's disease (BD) is a chronic systemic inflammatory disease. Inflammatory reactions trigger the oxidative stress and oxidants decrease the level of antioxidants. In the present study, we aimed to determine serum oxidative/antioxidative status in patients with BD. Serum antioxidative status was evaluated by measuring total antioxidant capacity (TAC), paraoxonase 1, arylesterase, sulfhydryl groups and ceruloplasmin in patients with BD and in healthy controls. Serum oxidative status was evaluated by measuring total peroxide (TP), lipid hydroperoxides and oxidative stress index (OSI). OSI was calculated by percent ratio of TP to TAC. Serum levels of TAC, sulfhydryl groups and activities of paraoxonase 1, arylesterase, and ceruloplasmin were significantly lower in patients than in controls (p < 0.001 for all). In contrast, TP, lipid hydroperoxides and OSI values were significantly higher in patients than in controls (p < 0.001 for all). Further, the level of TAC was negatively correlated with the levels of TP, lipid hydroperoxides and OSI both in the BD (r = -0.578, p < 0.01; r = -0.559, p < 0.01 and r = -0.552, p < 0.01, respectively) and the control groups (r = -0.469, p < 0.05; r = -0.351, p < 0.05 and r = -0.391, p < 0.05, respectively). These results indicate that the oxidant parameters increased and antioxidant parameters decreased in patients with BD; therefore, these patients might have been exposed to oxidative stress. We suggest that impaired oxidant/antioxidant balance should be taken into consideration in the follow-up of patients with BD.

Paraoxonase-1 activity as a marker of atherosclerosis is not associated with low bone mineral density in healthy postmenopausal women

The aging process is associated with an increasing prevalence of osteoporosis and atherosclerosis, but it is uncertain if these two conditions are interrelated. Serum paraoxonase-1 (PON1) is a high-density lipoprotein (HDL) associated enzyme that has been implicated in the pathogenesis of atherosclerosis. Our aims of the study were to investigate (1) serum paraoxonase and arylesterase activities and, lipid hydroperoxide (LOOH) levels in healthy postmenopausal women and (2) whether there were any associations between these enzyme activities and bone mineral density (BMD). A total of 97 generally healthy postmenopausal women were enrolled in the study. BMD was measured at lumbar spine (LS) and femoral neck (FN) with dual energy X-ray absorptiometry. Serum paraoxonase and arylesterase activities were measured spectrophotometrically. LOOH levels were measured by iodometric assay. In this population, 50 (51%) women had BMD T scores < -2.5 at the LS and/or FN defined as osteoporosis and 47 (49%) of them had normal BMDs. Serum paraoxonase, arylesterase, and LOOH activities were not significantly different between osteoporotic and nonosteoporotic postmenopausal women. There were also no correlations between paraoxonase, arylesterase, LOOH activities, and LS BMD and FN BMD. We conclude that there may be not good evidence to support a direct relationship between osteoporosis and atherosclerosis in these subjects. However, prospective studies with larger groups are needed to investigate this issue further.

Paraoxonase and arylesterase levels in rheumatoid arthritis

It was reported that lipid peroxidation (LPO) products increase in rheumatoid arthritis (RA) patients and increased LPO products reduce many antioxidants. Lipid hydroperoxides (LOOHs) are byproduct of LPO. Paraoxonase (PON), arylesterase (ARE), free sulfhydryl (SH) groups, and ceruloplasmin (CP) are enzymes or proteins with antioxidant characteristics. This study aims to determine the levels of LOOHs and SH, and the activities of PON1, ARE, and CP in RA patients. The study included 47 active RA cases and 23 healthy volunteers. The levels of LOOHs and SH, and the activities of PON1, ARE, and CP were determined using appropriate methods. Student's t test and Spearman's correlation analysis methods were employed in the statistical evaluation. The level of LOOHs was found to be higher (p<0.001), while the level of SH and the activities of PON1, ARE, and CP were found to be lower (p<0.001, <0.001, <0.01, and <0.01, respectively) in the RA patient group when compared with the control group. There was a negative correlation between the level of LOOHs and the activity of PON1 in the patient group (r= -0.420 and p<0.01). The results of our study indicate increased oxidant and decreased antioxidant presence in RA patients. PON1 and ARE are known to have antiatherosclerotic effects in addition to their antioxidant characteristics. As the decrease in these antioxidants, resulting from increased oxidative stress in RA patients, development of atherosclerosis besides tissue injury seems inevitable.

Effect of methionine supplementation on endothelial function, plasma homocysteine, and lipid peroxidation

BACKGROUND

Acetaminophen (paracetamol) poisoning is a major source of morbidity and mortality. It has been proposed that methionine be incorporated into acetaminophen tablets routinely as a protective mechanism. Methionine has been shown to be effective in the treatment of acetaminophen toxicity and a combination preparation of acetaminophen and methionine may prevent toxicity. However, there has been some concern that chronic methionine supplementation may be associated with vascular disease. The aim of the study was to investigate if methionine supplementation causes changes in endothelial function, plasma homocysteine, or lipid peroxidation which may be associated with atherosclerosis.

METHODS

Sixteen healthy volunteers were studied. Forearm blood flow in response to local intra-arterial infusion of acetylcholine to assess endothelium-dependent vasodilatation and sodium nitroprusside to assess endothelium-independent vasodilatation was measured by venous occlusion plethysmography. Plasma homocysteine and lipid peroxidation, measured as thiobarbituric acid reactive substances, were measured using high-performance liquid chromatography. Forearm vascular responses, plasma homocysteine concentrations, and thiobarbituric acid reactive substances were measured at baseline and following methionine supplementation.

RESULTS

There was no significant difference in endothelial-dependent vascular responses after acute (methionine 250 mg orally, p > 0.05), 1 month of low-dose (methionine 250 mg daily, p > 0.05), or 1 week of high-dose (methionine 100 mg/kg daily, p > 0.05) methionine administration. There was no significant difference in plasma homocysteine concentrations after acute (p > 0.05) or 1 month of low-dose (p > 0.05) methionine administration. However, 1 week of high-dose methionine (100 mg/kg) administration daily significantly increased homocysteine concentrations (p < 0.0015). Thiobarbituric acid reactive substances were unchanged during the period of study (p > 0.05).

CONCLUSIONS

Methionine supplementation does not impair endothelial-dependent vascular responses in healthy volunteers. Although high-dose methionine administration causes elevation of plasma homocysteine concentrations, doses similar to those used in combination preparations with acetaminophen do not affect plasma homocysteine concentrations.

Effect of dietary fish oil supplementation on peroxidation of serum lipids in patients with non-insulin dependent diabetes mellitus

Lipid peroxidation may be important in the development of cardiovascular disease, a common cause of mortality and morbidity in non-insulin dependent diabetes mellitus (NIDDM). We assessed the degree of lipid peroxidation by measuring plasma malondialdehyde, as thiobarbituric acid reacting substances (TBARS), in 23 non-insulin diabetic patients. Plasma levels of standardised alpha-tocopherol (vitamin E), lipid content of whole plasma and lipoprotein fractions, glycosylated haemoglobin, glycosylated low density lipoprotein (LDL) and fasting blood glucose were also measured. On completion of the baseline studies patients randomly received either fish oil or matching olive oil capsules in a double blind crossover fashion for 6 weeks followed by a 6 week washout period and a final 6 week treatment phase. Studies, identical to the initial baseline studies, were performed at the end of the of the active treatment periods at 6 and 18 weeks. Treatment with olive oil did not change levels of TBARS, vitamin E or indices of glycaemic control compared with baseline. Total cholesterol and triglyceride (TG) content of plasma and lipoprotein fractions were not significantly altered. Treatment with fish oil resulted in elevation of TBARS (P < 0.001) and reduction of vitamin E (P < 0.01) compared with baseline and olive oil treatment. Plasma cholesterol was unchanged. A reduction in plasma TG compared with baseline occurred but failed to reach significance (P =0.07). Changes in apo B containing lipoproteins induced by fish oil failed to reach significance. No significant changes were observed in concentration or composition of high density lipoprotein (HDL). Fish oil treatment showed no change in glycaemic control as assessed by glycosylated haemoglobin and LDL although a rise in fasting blood glucose just failed to reach significance (P = 0.06). Lipid peroxidation in NIDDM can be exacerbated by dietary fish oil. This potentially adverse reaction may limit the therapeutic use of fish oils in such patients.

Oxidative stress and erythrocyte membrane fluidity in patients undergoing regular dialysis

Oxidative damage due to free radical production is increased in uraemic patients and has been suggested as a possible factor contributing to the anaemia of chronic renal failure (CRF) and the pathogenesis of atherosclerosis. Oxidative stress was assessed in 40 patients with CRF maintained by either haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD) and in 18 healthy controls. Lipid peroxidation (assessed as malondialdehyde, MDA), total glutathione (TG), antioxidant enzyme (glutathione reductase (GSHRx), glutathione peroxidase (GSHPx) and superoxide dismutase (SOD)) activity and antioxidant associated trace metal (selenium, copper, zinc) levels were studied. Erythrocyte membrane fluidity was examined using the fluorescent probe 1,6 diphenyl-1,3,5-hexatriene (DPH). The results indicate increased levels of oxidative stress and altered erythrocyte membrane fluidity in patients treated with CAPD compared with controls and patients treated with HD. Only minor changes were observed in patients treated with HD. Altered free radical activity, oxidative stress and altered erythrocyte membrane fluidity observed in patients with CRF may contribute to the increase in vascular disease in such patients and to the anaemia of CRF.

Photodynamic sensitizers assay: rapid and sensitive iodometric measurement

A rapid, sensitive and simple spectrophotometric method for the detection of 1O2 produced by photodynamic photosensitizers in slightly acid and air-saturated aqueous solutions has been developed. The method is based on the reaction of 1O2 (produced by photodynamic processes) with I- in the presence of ammonium molybdate as a catalyst. The reaction product I3-, proportional to 1O2, is followed spectrophotometrically at 355 nm. Several ways of avoiding interference with other oxidizing compounds, either present before or produced during the irradiation, are described.

Lipid peroxides in blood from patients with atherosclerosis of coronary and peripheral arteries

Lipid peroxides in plasma were determined in 100 patients with coronary artery disease, in 100 patients with peripheral artery disease and in 100 persons without any clinical symptoms of coronary or peripheral artery disease. The concentrations of lipid peroxides were significantly higher in patients with atherosclerosis (both coronary and peripheral arteries) than in controls. There was no difference between lipid peroxides in patients with coronary and peripheral artery disease. Lipid peroxides in plasma were similar in subgroups of patients with coronary artery disease without a history of myocardial infarct and those who had had myocardial infarct. In subgroups of patients with peripheral artery disease divided according to the severity of peripheral atherosclerosis a positive association between the concentration of lipid peroxides in plasma and the severity of disease was observed. In all groups there was a significant correlation between the age of examined persons and lipid peroxides in plasma; however, the concentration of lipid peroxides in plasma was statistically higher in patients with atherosclerosis than in the control age matched group. The correlation between lipid peroxides and total cholesterol as well as triglycerides were weak and not statistically significant in most of the examined groups. The results of this study provide clinical support for experimental data indicating that peroxidation of lipids is an important factor in the formation of atherosclerotic changes. They also indicate that determination of plasma lipid peroxides may give important supplementary information in monitoring patients with clinical symptoms of atherosclerosis.