Serum lipoperoxide level in patients suffering from liver diseases

Malondialdehyde, an Oxidative Stress Marker in Oral Squamous Cell Carcinoma-A Systematic Review and Meta-Analysis

Objective: To qualitative and quantitatively review published literature assessing the oxidative stress marker malondialdehyde (MDA) in oral squamous cell carcinoma (OSCC). Methodology: Pubmed (MeSH), Science Direct, Scopus, Web of Science, Willey Online Library, Cochrane, and Cross Reference were searched for studies assessing MDA levels in OSCC samples. Results: From the 1008 articles identified, 849 were excluded based on title and abstract screening due to duplication and irrelevance to the topic of interest. Full-text assessment of the remaining 159 articles led to the inclusion of only 46 articles that satisfied the selection criteria. Of these, only 26 studies had data compatible for quantitative analysis. The MDA levels in OSCC groups are significantly increased (p < 0.00001) in plasma, serum, and saliva samples in the majority of the studies evaluated. In contrast, MDA levels in OSCC tissue samples are significantly attenuated (p < 0.00001) compared to healthy controls, supported by fewer studies. Conclusions: The augmented MDA levels in plasma, serum, and saliva samples of the OSCC reflect the heightened oxidative stress level accurately. Further studies are required to understand the attenuated MDA levels in the tissue samples of OSCC. Correlation analysis between MDA levels with established clinicopathological prognostic markers could aid in formulating oxidative stress-based prognostication and treatment planning.

Oxidative stress modulation in hepatitis C virus infected cells

Hepatitis C virus (HCV) replication is associated with the endoplasmic reticulum, where the virus can induce cellular stress. Oxidative cell damage plays an important role in HCV physiopathology. Oxidative stress is triggered when the concentration of oxygen species in the extracellular or intracellular environment exceeds antioxidant defenses. Cells are protected and modulate oxidative stress through the interplay of intracellular antioxidant agents, mainly glutathione system (GSH) and thioredoxin; and antioxidant enzyme systems such as superoxide dismutase, catalase, GSH peroxidase, and heme oxygenase-1. Also, the use of natural and synthetic antioxidants (vitamin C and E, N-acetylcysteine, glycyrrhizin, polyenylphosphatidyl choline, mitoquinone, quercetin, S-adenosylmethionine and silymarin) has already shown promising results as co-adjuvants in HCV therapy. Despite all the available information, it is not known how different agents with antiviral activity can interfere with the modulation of the cell redox state induced by HCV and decrease viral replication. This review describes an evidence-based consensus on molecular mechanisms involved in HCV replication and their relationship with cell damage induced by oxidative stress generated by the virus itself and cell antiviral machinery. It also describes some molecules that modify the levels of oxidative stress in HCV-infected cells.

Alleviation of kainic acid-induced brain barrier dysfunction by 4-o-methylhonokiol in in vitro and in vivo models

This experiment was designed to investigate whether 4-O-methylhonokiol (MH), a principal ingredient of Magnolia (M.) officinalis bark, alleviated acute intraperitoneal (i.p.) kainic acid- (KA-) induced brain blood barrier dysfunction (BBBD) via pathological examination and cytological analyses of the brain tissues of mice. KA (10–30 mg/kg) time- and dose-dependently increased the water content of brain tissues and induced edema and encephalopathy. However, pretreatment with MH (5 and 20 mg/kg, i.p.) significantly reduced the water content of the brain compared to that observed in the KA control group. Furthermore, MH significantly and dose-dependently reversed the remarkable variations in evan's blue dye (EBD) staining and malondialdehyde (MDA) levels that were induced by KA (10 mg/kg, i.p.). MH also decreased the elevated seizure scores that were induced by KA (10 mg/kg, i.p.) in mice in a manner similar to scavengers such as DMTU and trolox. Additionally, MH significantly scavenged intracellular ROS and Ca²⁺ within hippocampal cells. The tight junction seals mediated by claudin (Cld-5) were also found to be modulated by MH. MH efficiently reduced 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀, 52.4 mM) and ^•OH with an electron spin resonance (ESR) signal rate constant of 4 × 10⁹ M⁻¹ · S⁻¹, which is close to the reactivity of the vitamin E analog trolox. Taken together, these results suggest that MH may enhance radical scavenging in lipid and hydrophobic environments, which may be important for the physiological activity of the barrier.

Red ginseng extract attenuates kainate-induced excitotoxicity by antioxidative effects

This study investigated the neuroprotective activity of red ginseng extract (RGE, Panax ginseng, C. A. Meyer) against kainic acid- (KA-) induced excitotoxicity in vitro and in vivo. In hippocampal cells, RGE inhibited KA-induced excitotoxicity in a dose-dependent manner as measured by the MTT assay. To study the possible mechanisms of the RGE-mediated neuroprotective effect against KA-induced cytotoxicity, we examined the levels of intracellular reactive oxygen species (ROS) and [Ca²⁺]_i in cultured hippocampal neurons and found that RGE treatment dose-dependently inhibited intracellular ROS and [Ca²⁺]_i elevation. Oral administration of RGE (30 and 200 mg/kg) in mice decreased the malondialdehyde (MDA) level induced by KA injection (30 mg/kg, i.p.). In addition, similar results were obtained after pretreatment with the radical scavengers Trolox and N, N′-dimethylthiourea (DMTU). Finally, after confirming the protective effect of RGE on hippocampal brain-derived neurotropic factor (BDNF) protein levels, we found that RGE is active compounds mixture in KA-induced hippocampal mossy-fiber function improvement. Furthermore, RGE eliminated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and the IC₅₀ was approximately 10 mg/ml. The reductive activity of RGE, as measured by reaction with hydroxyl radical (^•OH), was similar to trolox. The second-order rate constant of RGE for ^•OH was 3.5–4.5 × 10⁹ M⁻¹·S⁻¹. Therefore, these results indicate that RGE possesses radical reduction activity and alleviates KA-induced excitotoxicity by quenching ROS in hippocampal neurons.

Biochemical studies of transient intermediates in relation to chemical carcinogenesis

Many chemical carcinogens must be metabolized to chemically reactive transient species before they can exert their full toxic action on mammalian cells. In general, this metabolic activation is performed by NADPH-dependent enzymes in the endoplasmic reticulum; the NADPH-cytochrome P-450 electron-transport chain is very important in this respect. Biochemical studies on the chemical reactivities of such transient intermediates require the application of various fast-reaction and free-radical techniques: the use of such techniques is illustrated by reference to the metabolism of carbon tetrachloride. CCl4 is metabolized by liver endoplasmic reticulum in the presence of NADPH to a highly reactive product, probably CCl3; this activation of CCl4 results in covalent binding of CCl3 and lipid peroxidation. The steady-state concentration of CCl3 is too low to be measured directly by e.s.r. spectroscopy but radical species can be accumulated with spin-trap techniques. The CCl3 radical can be generated by pulse radiolysis and the ensuing reactions with biologically important neighbouring species can be followed in the microsecond range by kinetic spectroscopy. The results point to the high reactivity of CCl3 and its restriction to a microenvironment within the endoplasmic reticulum. Highly reactive electrophilic radicals (e.g. CCl3) can initiate lipid peroxidation in biomembranes and this is associated with changes in polyunsaturated fatty acids and in membrane fluidity. The results are discussed in relation to carcinogen activation, to free-radical-mediated reactions in biomembranes, and to the general thesis that the production of reactive aldehydes by lipid peroxidation may act as a 'coarse control' of cell division.

LycoRed as an alternative to hormone replacement therapy in lowering serum lipids and oxidative stress markers: A randomized controlled clinical trial

AIM

Menopause is a pro-atherogenic state with a sharp rise in the incidence of coronary artery disease. This pilot study was designed as an equivalence randomized clinical trial to explore the potential of LycoRed (containing 2000 microg lycopene) as an alternative to hormone replacement therapy (HRT) for the prevention of coronary artery disease in postmenopausal women.

METHODS

Forty-one healthy postmenopausal women were randomly allocated to receive either continuous combined HRT (n = 21) or LycoRed (n = 20) for six months. Serum lipid profile, marker of lipid peroxidation (malondialdehyde), and the level of endogenous antioxidant (glutathione) were measured at the baseline, and 3 and 6 months after the intervention in both groups.

RESULTS

At 6 months, HRT resulted in a significant decrease in total cholesterol (TC) level by 23.5%, low-density lipoproteins (LDL) by 19.6%, and an increase in high-density lipoproteins (HDL) by 38.9%. The LycoRed group showed similar changes in TC (-24.2%), LDL (-14.9%) and HDL (+26.1%). Triglyceride levels showed a smaller though significant increase at 6 months, but not at 3 months, in both groups. There was no significant change in the very LDL (VLDL) level in either group. Malondialdehyde levels decreased significantly by 16.3% and 13.3%, whereas glutathione levels increased significantly by 5.9% and 12.5% in HRT and LycoRed groups, respectively.

CONCLUSION

Both HRT and LycoRed had a favorable effect on serum lipids and oxidative stress markers which were comparable. LycoRed can be used as an alternative to HRT to reduce the risk of atherosclerosis in postmenopausal women.

White spot syndrome virus infection decreases the activity of antioxidant enzymes in Fenneropenaeus indicus

White spot syndrome virus (WSSV) is the causative agent of White Spot disease of shrimp, causing mass mortalities in aquaculture. WSSV infection causes oxidative stress by the release of reactive oxygen species (ROS) that are toxic to the cells. The antioxidant enzymes associated with oxidative stress during the process of pathogenesis of WSSV in the infected tissues (hemolymph, hepatopancreas, gills and muscle) of Fenneropenaeus indicus were quantitatively determined at different time intervals post infection (0, 24, 48, 72 and after 72 h (moribund)). The level of lipid peroxidation, the activities of superoxide dismutase, catalase, glutathione peroxidase, and also the activities of the non-enzymic antioxidants glutathione-S-transferase, reduced glutathione and glutathione reductase in healthy and WSSV-infected hemolymph, hepatopancreas, gills and muscle of F. indicus showed marked differences at different times during the course of infection. The level of lipid peroxidation was higher in WSSV-infected muscle, hemolymph, gills and hepatopancreas than in uninfected F. indicus. Significant reductions in the activities of superoxide dismutase, catalase, glutathione-S-transferase, reduced glutathione, glutathione peroxidase and glutathione reductase were observed in WSSV-infected compared with uninfected animals. The increased lipid peroxidation in WSSV-infected shrimp may be due to increased oxidative stress in the cells as a result of depletion of antioxidant scavenger systems. The reduced activity of antioxidant enzymes in WSSV-infected animals could be due to inactivation of antioxidant enzymes by oxidative stress thereby generating free radicals, which accumulate in the cells. Further understanding of the biochemical alterations induced by viral infections, including changes in the antioxidant status and oxidative stress, could help to advance the therapeutic armamentarium for control of WSSV in shrimp.

Behavioural and biochemical effects of fractions prepared from Banxia Houpu decoction in depression models in mice

Banxia-houpu decoction is widely used in therapy for depression in China. The water-EtOH extract (WE-1) and chloroform-soluble fraction (WE-1-2) of Banxia-houpu decoction reduced the duration of immobility in the tail suspension test (TST) and the forced swimming test (FST), the efficacy of the latter was higher than that of the former. The petroleum-soluble fraction (WE-1-1), ethyl acetate-soluble fraction (WE-1-3) and water-soluble fraction (WE-1-4) tended to possess antiimmobility effects in the TST. After a 21-day treatment, the potency of WE-1-2 was almost equivalent to that of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), in the TST, but WE-1-2 showed a lower efficiency than fluoxetine in the FST. WE-1, as well as WE-1-3, was found to increase serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels in mouse hippocampus and striatum, the activities of WE-1 and WE-1-3 were much stronger than that of fluoxetine. Moreover, WE-1-1, WE-1-2 and WE-1-4 significantly elevated 5-HT and 5-HIAA levels only in the striatum, the degrees of increase of 5-HT and 5-HIAA levels were comparable to that of fluoxetine, which significantly enhanced the levels in all regions of animal brains. Neither fractions or fluoxetine affected norepinephrine (NE) and dopamine (DA) levels in the animal brains. It was found that WE-1, WE-1-2 and fluoxetine significantly decreased serum and liver malondialdehyde (MDA) levels in the study. These results provide evidence for a potential role of antidepressive activities in the therapeutic effects of the Banxia-houpu decoction.

Protective effect of ginseng extract against apoptotic cell death induced by 2,2',5,5'-tetrachlorobiphenyl in neuronal SK-N-MC cells

Oxidative stress plays an important role in the pathological processes of neurodegenerative diseases. Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants, some of which may be neurotoxic. 2,2',5,5'-Tetrachlorobiphenyl (PCB 52) induces apoptotic death in human neuronal SK-N-MC cells, as demonstrated by gel electrophoresis, which demonstrates the proteolytic cleavage of beta-catenin and poly(ADP-ribose) polymerase (PARP) and the characteristic ladder patterns of DNA fragmentation. In the present study, we investigated whether Panax ginseng extract protect human neuronal SK-N-MC cells from PCB 52-induced apoptosis. The addition of 500 microg/ml of ginseng extract to a culture medium significantly protected neuronal cell from the apoptosis mediated by PCB 52 and remarkably attenuated lipid peroxidation, the generation of reactive oxygen species, and DNA fragmentation, and markedly reduced the PCB 52 induced proteolytic cleavage of beta-catenin and PARP. These results show that Panax ginseng extract protects human neuronal SK-N-MC cells from the apoptosis induced by PCB 52. We suggest that Panax ginseng extracts may protect neuronal cells from oxidative injury.

Does underwater rugby stimulate the over-production of reactive oxygen species?

Antioxidant enzymes in erythrocytes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and antioxidant sex hormone oestradiol in serum and malondialdehyde (MDA) production as a marker of lipid peroxidation in erythrocytes were investigated in male and female underwater rugby (UWR) players. Results showed that except for GSH-Px activity in female players, all antioxidant enzymes increased significantly (p < 0.05) after an UWR game. It was interesting to note that while the concentration of oestradiol in female players did not change, it increased significantly (p < 0.05) in male players. Lipid peroxidation (LPO) levels in female players as well as oestradiol concentration did not change significantly (p > 0.05) whereas LPO levels in male players increased significantly (p < 0.05) compared to pre-exercise values. In conclusion, the results showed that underwater rugby can stimulate over-production of ROS and antioxidant systems and affect oestradiol levels in male players. Because of increased LPO levels observed in male players, complex antioxidant supplementation including co-factors of antioxidant enzymes such as Cu, Zn, Fe, Se and antioxidant vitamins such as vitamin C and E may be recommended to players before the UWR game.

Superoxide dismutase in pediatric palatine tonsils and adenoids and its related clinical parameters

PURPOSE

The objective of this study was to investigate a protective system of pediatric palatine tonsils and adenoids against superoxide radicals (O(2)(-)) and to evaluate the clinical factors including otitis media with effusion that are related to both the expression and activities of copper zinc superoxide dismutases (CuZnSODs).

DESIGN

CuZnSODs in the palatine tonsils and adenoids were studied using immunohistochemistry and reverse-transcription polymerase chain reaction.

RESULTS

Immunohistochemistry showed that CuZnSODs distribute in the crypt epithelium, mucous membrane, mantle zone, and extrafollicular area of the pediatric adenoids as well as in the palatine tonsils. Otitis media with effusion and paranasal sinusitis were related to CuZnSODs expression in the pediatric adenoids. In addition, the frequency of tonsillitis and presence of recent tonsillitis were significantly related to CuZnSODs expression in the pediatric tonsils (P <.05).

CONCLUSIONS

In both the pediatric palatine tonsils and adenoids, the mechanism of tissue protection against infection and frequent inflammatory reactions may be closely related to CuZnSODs expression. There may be close relationship between the increased level of O(2)(-) that leads to an increase in CuZnSODs in the pediatric adenoid tissue and the development of otitis media.

Menopause, coronary artery disease and antioxidants

The aim of this study was to examine the influence of menopause on the activity of primary intracellular antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) as well as on the level of total antioxidant status (TAS) in healthy women and women with coronary artery disease (CAD). We studied 140 women divided into two groups. The first group (controls) consisted of 99 healthy women aged between 18 and 55 years) classified into three subgroups: pre-menopausal women (Pre-M; n=48), peri-menopausal women (Peri-M; n=22) and post-menopausal women (Post-M; n=29). The second group consisted of 41 women with CAD aged between 48-68 years, classified into two subgroups: Peri-M (n=20) and Post-M (n=21). The activity of GPx and the level of TAS were significantly decreased in Peri-M (p<0.005) and Post-M groups (p<0.001) in comparison with the Pre-M group. SOD was decreased in Peri-M and Post-M groups compared with the Pre-M group, but this was statistically not significant. The activity of SOD and GPx as well as TAS were significantly decreased in the Post-M group compared with the Peri-M group with CAD (p<0.001). The activity of the antioxidant enzymes in Peri-M and Post-M groups was significantly decreased (p<0.02) in comparison with the control group. TAS was not changed in women with CAD in comparison with controls. In conclusion, menopause leads to the reduction of the level of antioxidants, especially in women with CAD.

Ovariectomy Accelerates Photoaging of Rat Skin¶

We have previously reported the formation of wrinkles, a decrease in skin elasticity and a loss in the linearity of dermal elastic fibers in rat hind limb skin irradiated with ultraviolet radiation in wavelength ranging 290-320 nm (UVB) at a suberythemal dose for 6 weeks. Estrogens are considered effective in preventing photoaging in postmenopausal females, but the role of estrogen in the skin remains unclear. In this study we have evaluated the influence of short-term chronic UVB irradiation at a suberythemal dose on the skin of ovariectomized rats. An ovariectomy or a sham operation was performed on each 3 week-old female Sprague-Dawley rat. Starting 1 week after the operation the hind limb skin of each rat was irradiated with UVB at a suberythemal dose (130 mJ/cm2) three times a week for 3 or 6 weeks. Decreases in elasticity and wrinkle formation in the skins of ovariectomized animals were induced more quickly than in the skins of sham-operated animals following UVB irradiation. The linearity of elastic fibers in the ovariectomy group decreased significantly compared with the sham-operation group, but erythema in the ovariectomy group was induced more readily than in the sham-operation group following UVB irradiation. These findings suggest that decreases in the estrogen levels after ovariectomy accelerate photoaging in terms of the morphology and physical properties of the skin surface and the three-dimensional structure of elastic fibers.

Thioredoxin levels in the sera of untreated viral hepatitis patients and those treated with glycyrrhizin or ursodeoxycholic acid

Thioredoxin (TRX), a thiol-containing protein, is induced by various oxidative stresses. Serum TRX levels were measured with a sandwich enzyme-linked immunosorbent assay kit in 210 hepatitis C virus (HCV)-infected patients, 39 hepatitis B virus (HBV)-infected patients, and 17 healthy volunteers. The effects of hepatoprotective drugs on TRX levels were also examined. The median TRX levels were significantly higher in HCV-infected patients than in controls (34.2 vs. 23.5 ng/ml, respectively; p < 0.005), but were not elevated in HBV-infected patients (26.7 ng/ml). The TRX levels were significantly correlated with serum lipid peroxide levels and indocyanine green exclusion test values, and were markedly decreased following treatment with Stronger Neo-Minophagen C or ursodeoxycholic acid. In conclusion serum TRX levels, a marker of oxidative stress, were higher in patients with HCV infection than those with HBV infection and healthy controls. The therapeutic efficacy of hepatoprotective drugs may be connected with the decrease in oxidative stress in hepatitis patients.

Normothermic liver ischemia and antioxidant treatment during hepatic resections

The purpose of our study was to evaluate the clinical impact of reperfusion injury after normothermic ischemia during major liver resections and the effect of an intraoperative antioxidant infusion. This prospective randomized study comprised 50 patients; half of them (treatment group) were given an antioxidant infusion containing tocopherol and ascorbate immediately prior to reperfusion onset. Venous blood samples for the determination of MDA-TBARS (malondialdehyde-thiobarbituric acid reactive substances) by a HPLC-based test as a marker of lipid peroxidation were taken prior to ischemia, 30 min after reperfusion onset and at the end of the operation. In the control group there was a significant increase of MDA-TBARS (p = 0.001) at 30 min after reperfusion onset. At the end of the operation the values had returned to the initial level. The treatment group showed only a marginal increase (p-value for the difference between the two groups: 0.007). After exclusion of the patients with histologically proven advanced cirrhosis the increase in the control group (p < 0.001) and the difference between the increase in the two groups (p = 0.001) became more significant. Prothrombin time was also significantly better in the treatment group (p = 0.003). Postoperative complications such as prolonged liver failure, bleeding disorders and infections were seen more often in the control group. In our study MDA-TBARS was increased after liver ischemia, but in patients with advanced cirrhosis the effect was smaller or even absent. This increase and possible clinical consequences of reperfusion injury could be reduced by intraoperative administration of an antioxidant infusion.

Oxidant and antioxidant activity changes in patients with oral cancer and treated with radiotherapy

Of all the clinical disciplines, radiotherapy probably has the most secure and scientific foundations. In oral cancer, radiotherapy may be used as the sole treatment or in combination with other modalities of treatment. Blood samples were collected from stage III oral cancer patients attending the Oncology Department, Bernard Institute of Radiation and Oncology, Chennai Medical College, Chennai, India, before initiating radiotherapy and after the sixth week of radiotherapy. The effect of radiation on oral cancer patients has been studied using activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathione reductase (GR), glutathione-S-transferase (GST), glucose-6-phosphate dehydrogenase (G6PDH) and levels of malondialdehyde (MDA). The levels of MDA showed a significant increase in untreated and radiation oral cancer patients when compared with normal subjects. The activities of red blood cell (RBC) hemolysate antioxidant enzymes such as SOD, catalase, GPX, GR, GST and G6PDH showed a significant decrease, representing the lack of antioxidant defense. Radiation induces lipid peroxidation by inactivating the antioxidant enzymes, thereby rendering the system inefficient in management of the free radical attack. Thus, the degree of radiation affects the extent of the depression of the antioxidant enzyme activities and increases lipid peroxidation.

Plasma ubiquinone to ubiquinol ratio in patients with hepatitis, cirrhosis, and hepatoma, and in patients treated with percutaneous transluminal coronary reperfusion

To assess the degree of oxidative stress, we measured plasma ubiquinone-10 percentage (%CoQ-10) in total amounts of ubiquinone-10 in patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma, and in age-matched control subjects, %CoQ-10 values were 12.9 +/- 10.3 (n = 28), 10.6 +/- 6.8 (n = 28), 18.9 +/- 11.1 (n = 20), and 6.4 +/- 3.3 (n = 16), respectively, showing a significant increase in oxidative stress in patient groups as compared to control subjects. There were no differences in total amounts of ubiquinone-10 and ubiquinol-10 among the four groups. We next measured %CoQ-10 in plasmas obtained from nine patients treated with percutaneous transluminal coronary angioplasty (PTCA). Plasmas were collected when hospitalized, and at the time (0, 4, 8, 12, 16, and 20 hr, and 1, 2, 3, 4, and 7 days) after the PTCA. %CoQ-10 values before and right after PTCA were 9.9 +/- 2.8 and 11.4 +/- 2.0, respectively, reached a maximum (20-45) at 1 or 2 days later, and decreased to 7.9 +/- 2.7 at 7 days after PTCA, indicating an increase in oxidative stress in patients during coronary reperfusion.

Serum malondialdehyde: possible use for the clinical management of chronic hepatitis C patients

Serum lipid peroxidation products are increased in inflammatory liver disease and, as we previously reported, also in chronic hepatitis C. We have performed a specific assay of malondialdehyde, the reported most abundant product of lipid peroxidation, in serum of twenty four chronic hepatitis C patients, before, during, and after interferon treatment. Liver biopsies were performed in each patient before and after interferon treatment. The results show higher serum malondialdehyde values in chronic hepatitis C patients than healthy subjects (n = 68) before interferon treatment (p < .001). Mean value of serum malondialdehyde levels after interferon treatment was significantly lower than before it (p < .002). Associating the histopathological findings in each of the 48 biopsies performed, with serum malondialdehyde and alanine aminotransferase activity levels, of the sample obtained the same day of biopsy, a much better correspondence with the histopathological severity was observed for malondialdehyde concentration than for alanine aminotransferase activity. These levels decreased significantly after interferon treatment. However, when the patients were grouped in responding (group I; n = 9) and non-responding (group II; n = 15) to interferon treatment, according to the histopathological findings before and after interferon, the values of group I before interferon treatment were significantly higher than group II (p < .03). Thus, a potential predictive value could be ascribed to the serum malondialdehyde levels before interferon treatment in these patients. We propose the utility of the specific assay of malondialdehyde for the clinical management of chronic hepatitis C patients.

Lipid peroxidation products and antioxidants in human disease

Lipid peroxidation (LPO) is a free radical-related process that in biologic systems may occur under enzymatic control, e.g., for the generation of lipid-derived inflammatory mediators, or nonenzymatically. This latter form is associated mostly with cellular damage as a result of oxidative stress, which also involves cellular antioxidants in this process. This article focuses on the relevance of two LPO products, malondialdehyde (MDA) and 4-hydroxynonenal (HNE), to the pathophysiology of human disease. The former has been studied in human serum samples of hepatitis C virus-infected adults and human immunodeficiency virus-infected children. In these two cases it is shown that the specific assay of serum MDA is useful for the clinical management of these patients. The presence of MDA in subretinal fluid of patients with retinal detachment suggests the involvement of oxidative stress in this process. Moreover, we were able to report the dependence of this involvement on the degree of myopia in these patients. The assay of MDA contents in the peripheral nerves of rats fed a chronic alcohol-containing diet or diabetic mice also confirms the pathophysiologic role of oxidative stress in these experimental models. In these two cases, associated with an increase in tissue LPO products content, we detected a decrease of glutathione peroxidase (GSHPx) activity in peripheral nerve, among other modifications. We have demonstrated that in vitro HNE is able to inhibit GSHPx activity in an apparent competitive manner, and that glutathione may partially protect and/or prevent this inactivation. The accumulation of LPO products in the brain of patients with Alzheimer's disease has also been described, and it is on the basis of this observation that we have tried to elucidate the role of oxidative stress and cellular antioxidants in beta-amyloid-induced apoptotic cell death of rat embryo neurons. Finally, we discuss the possible role of the observed vascular effects of HNE on human arteries.

Oxidative stress in patients with hepatitis, cirrhosis, and hepatoma evaluated by plasma antioxidants

We have applied our method for the simultaneous detection of plasma ubiquinol-10 (reduced form) and ubiquinone-10 (oxidized form) (S. Yamashita and Y. Yamamoto, Anal. Biochem. 250, 66-73, 1997) to plasmas of normal subjects (n = 16) and patients with chronic active hepatitis (n = 28), liver cirrhosis (n = 16), and hepatocellular carcinoma (n = 20) to evaluate the pressure of oxidative stress in these patients. The average ubiquinone-10 percentages (+/- S.D.) in total ubiquinone-10 and ubiquinol-10 in the four groups were 6.4 +/- 3.3, 12.9 +/- 10.3, 10.6 +/- 6.8, and 18.9 +/- 11.1, respectively, indicating a significant increase in ubiquinone-10 percentage in patient groups in comparison to normal subjects. These results and a significant decrease in the plasma ascorbate level in patient groups indicate that oxidative stress is evident after the onset of hepatitis and the subsequent cirrhosis and liver cancer.

Lipid peroxidation in presence of ebselen

Lipid peroxidation is initiated by cell damage. After homogenisation of porcine heart tissue in aqueous solution we observed the same lipid peroxidation products as detected after heart infarction. We used this observation to study the influence of ebselen (2-phenyl-1,2-benzoisoselenazol-3-(2H)-one) on the generation of oxidatively derived monohydroxy fatty acids and alpha-hydroxyaldehydes, typical lipid peroxidation (LPO) products. Heart tissue was homogenised before and after enzyme destruction and with addition of ebselen. The obtained LPO products were analysed by GC/MS after appropriate derivatisation and quantified by using internal standards. The amount of monohydroxy fatty acids and alpha-hydroxyaldehydes increased considerably in the porcine heart homogenates in which the enzymes were kept active. Addition of ebselen caused an additional significant increase of hydroxy fatty acids, while the increase of aldehydic compounds was less. These results confirm the glutathione peroxidase-like activity of ebselen but demonstrate also that it does not prevent lipid peroxidation.

Properties of low density lipoproteins relevant to oxidative modifications change paradoxically during aging

Atherosclerosis is a common problem among the elderly. Because lipid peroxidation is considered a contributor to the development of atherosclerosis, we compared oxidative properties of lipoproteins in an otherwise healthy (SENIEUR-classified) aged population (65-74 years) with young controls (18-30 years). Relative amounts of oxidatively altered low density lipoprotein (LDL), estimated by means of an antibody against LDL modified by 4-hydroxynonenal, a product of lipid peroxidation, were increased marginally in serum from the elderly (9.8 vs. 7.4%, P = 0.07). In contrast, isolated LDL from the elderly revealed a decreased susceptibility to in vitro oxidation: the lag time was increased (2.34 vs. 2.10 h, P < 0.01), and the maximal rate of LDL oxidation decreased (0.88 vs. 1.01 O.D./h, P = 0.001). However, there were no age-related changes in lipid composition of native LDL and consumption of fatty acids during in vitro oxidation. The serum concentrations of ascorbic acid and most lipophilic anti-oxidants (the latter expressed per g serum lipids) were significantly decreased in the elderly except tocopherols which tended to be higher. In conclusion, our data reveal paradox age-related alterations of LDL as to its behaviour in oxidation in vivo vs. in vitro.

Enzymatic production of hydroperoxides of unsaturated fatty acids by injury of mammalian cells

Hydroperoxides of unsaturated fatty acids (LOOHs) are generated by homogenisation of liver tissue, but not if the liver is boiled before homogenisation. This observation indicates that the LOOHs are produced in an enzymatic reaction. This assumption is corroborated by an analysis of the reduction products of LOOHs by gas chromatography/mass spectrometry (GC/MS). A main part of LOOHs is derived from linoleic acid and not from arachidonic acid. Massive cell damage occurs by myocardial infarction or other severe injuries; these events were found to be connected with generation of LOOHs. We suspect--considering the above outlined experiment--that the LOOH production is also mainly caused in these cases by activation of enzymes and not--as postulated--by an autocatalytic process. Increased amounts of LOOHs are found in many chronic diseases, e.g. in rheuma, atherosclerosis or psoriasis, obviously caused by a gradual damage of cells. Thus, the common root of an increased LOOH level might be cell injury.

Oxidative stress during viral infection: a review

The purpose of this review is to analyze the role of reactive oxygen species (ROS) in the pathogenesis of viral infections, an area of research that has recently gained momentum given the accumulation of evidence regarding the role of ROS in the pathogenesis of infection with the human immunodeficiency virus (HIV). Attention will be focussed on three classes of viruses: (1) RNA viruses, (2) DNA viruses, and (3) retroviruses, with particular attention to influenza viruses, hepatitis B virus, and HIV as representative examples of these three classes, respectively. For each type of virus, evidence for the following will be analyzed: (1) the effect of the virus on activation of phagocytic cells to release ROS and pro-oxidant cytokines such as tumor necrosis factor; (2) the effect of the virus on the pro-/antioxidant balance in host cells, including virally induced inhibition of antioxidant enzymes such as superoxide dismutase and virally induced increases in pro-oxidants such as nitric oxide; (3) effects of the redox state of the cell on the genetic composition of the virus as well as ROS-mediated release of host cell nuclear transcription factor-kappa-B, resulting in increased viral replication; and (4) efficacy of antioxidants as therapeutic agents in viral diseases of both animal models and patients.

Breath pentane and plasma lipid peroxides in ischemic heart disease

This study examined the relationship between breath pentane and plasma lipid peroxide levels sampled simultaneously in patients with stable angina (n = 17), unstable angina (n = 23), and controls (n = 10). Plasma lipid peroxides were measured in venous blood as the adduct formed between thiobarbituric acid and malondialdehyde (MDA) using high performance liquid chromatography. Pentane was measured in end-expiratory air using gas chromatography. MDA concentrations in stable (1.81 +/- 0.84 mumol/l) and unstable (1.5 +/- 1.23 mumol/l) angina were not different. However, both groups had significantly (p < 0.005) elevated MDA levels compared to controls (0.41 +/- 0.26 mumol/l). Breath pentane was 0.20 +/- 0.12 nmol/l in controls and not different from stable angina (0.26 +/- 0.20 nmol/l) or unstable angina (0.15 +/- 0.07 nmol/l). When the data from all three groups were combined, there was no correlation between pentane and MDA (rho = -0.09, p = 0.54). In five of the unstable angina patients treated with balloon angioplasty, MDA in pulmonary arterial blood rose by 69 +/- 15% (p < 0.01), and breath pentane rose by 73 +/- 20% (p < 0.01) immediately after balloon deflation. One minute after balloon deflation MDA and pentane had returned to preinflation levels. The results suggest that basal levels of pentane are less useful than MDA as an index of lipid peroxidation in patients with coronary artery disease. However, breath pentane appears to be a sensitive index of reperfusion-induced lipid peroxidation.

Can estrogens diminish exercise induced muscle damage?

Estrogens are female sex hormones that may also protect against peroxidative damage of membrane lipids and low density lipoproteins (LDL). Studies have reported that female rats have greater protection against free radical induced lipid peroxidation and muscle damage consequent to exercise than do male rats. It has been suggested that the lower susceptibility to exercise induced oxidative stress and muscle membrane disruption of female rats may be due primarily to the antioxidant and membrane stabilizing properties of estrogens. Studies on humans have indicated that the lower incidence of atherosclerosis seen in premenopausal females in comparison to males is due at least in part to the ability of estrogens to diminish LDL peroxidation. However, there is little evidence as to the potential of estrogens to protect human females from free radical induced peroxidation and muscle damage due to exercise. This paper reviews the evidence for membrane stabilization potential of estrogens and their possible mechanisms, and speculates as to the potential significance of this for human exercise.

Anti-proliferative effect of 2-methoxyestradiol on cultured smooth muscle cells from rabbit aorta

The proliferation of cultured smooth muscle cells from rabbit aorta was inhibited markedly by 2-methoxyestradiol, considerably by 2-hydroxyestradiol, and only slightly by 17 beta-estradiol. The effects at doses from 1 to 40 nmol/ml were cytostatic rather than cytocidal. 2-Methoxyestradiol could be useful to suppress excessive proliferation of arterial smooth muscle cells, and thus to prevent the progression of atherosclerosis.

Enhancement by ascorbic acid 2-glucoside or repeated additions of ascorbate of mitogen-induced IgM and IgG productions by human peripheral blood lymphocytes

In this study, the effect of ascorbic acid 2-glucoside (AA-2G), a stable derivative of ascorbic acid (AsA), or repeated additions of ascorbate on antibody productions by human peripheral blood lymphocytes (PBLs) was examined, and the physiological function of AsA was evaluated. When human PBLs were stimulated with Staphylococcus aureus Cowan I or pokeweed mitogen, AA-2G remarkably increased the numbers of IgM- and IgG-secreting cells which were detected by enzyme-linked immunospot assay. Although a single addition of ascorbate was without effect, the effect of AA-2G was remarkably inhibited by the addition of castanospermine, an alpha-glucosidase inhibitor; and moreover, repeated additions of AsA to the culture medium during the culture period enhanced the response to the same level as did a single addition of AA-2G. These results indicate that AsA has the ability to stimulate the immunoglobulin productions by AA-2G. The phytohemagglutinin-induced proliferative response of PBLs was also stimulated by AA-2G. The intracellular AsA content in PBLs cultured with AA-2G was maintained at relatively high levels during the culture period, whereas the content with a single dose of AsA reached nearly zero by the end of the experiment. These in vitro findings suggest that AA-2G and AsA function as potent immunostimulators of antibody production in humans and that the intracellular AsA content is a key parameter for establishing the immune response of PBLs.

Interferon decreases serum lipid peroxidation products of hepatitis C patients

Thiobarbituric acid reactive substances (TBARS) concentration in serum has been determined in healthy subjects and in patients suffering acute hepatitis and chronic cases of hepatitis C. Treatment with interferon of the chronic active hepatitis C patients, 5 x 10(6) U three times a week during 2 months, led in those patients whose SGPT activity normalized in serum, to a concomitant decrease in serum TBARS content. The possible theoretical involvement of peroxidation and antioxidants in this beneficial effect of interferon in hepatitis C patients is discussed. The results presented confirm the value of TBARS as laboratory test in the management of liver diseases and as a useful tool for the study of pathogenic and/or therapeutic mechanisms of this viral infection.

Changes of lipid peroxide levels in blood and liver tissue of patients with obstructive jaundice

Plasma lipid peroxide levels, hereafter referred to as PLP levels, were measured in a group of 40 apparently healthy controls and 64 cholelithiasis patients, 40 with and 24 without jaundice. Hepatic lipid peroxide (HLP) levels were also measured in 26 patients, 15 with and 11 without jaundice. There was a significantly higher mean concentration of PLP in the jaundiced patients than in the control or jaundice-free cases. However, the difference in PLP levels between the jaundice-free and the control cases was insignificant. Meanwhile, patients with jaundice had significantly higher HLP levels than those without jaundice. In the jaundiced cases, the increased PLP and HLP levels were clearly related to the serum levels of bilirubin respectively. In addition, the HLP levels were positively correlated with the PLP levels; however, in the non-jaundiced cases, there was little evidence of these two relationships. Patients with or without jaundice had lower plasma vitamin E levels in comparison to the control cases. The correlation of plasma vitamin E and PLP levels was weak in all of the jaundiced. However, when we subdivided the jaundiced into two groups, the correlation was strong in those with plasma vitamin E levels < 8.5 micrograms/ml, while the correlation was weak in those with plasma vitamin E levels > 8.5 micrograms/ml. Consequently, these results suggest that there is an involvement of lipid peroxidation in liver cells damaged by obstructive jaundice in cholelithiasis patients and there exists a negative correlation between low vitamin E and lipid peroxide levels in plasma.

Pulmonary pentane excretion increases with age in healthy subjects

Excessive lipid peroxidation occurs in various diseases. However, even in health low levels of lipid peroxidation can be detected by measuring the pulmonary excretion of pentane. Lipid peroxidation has been postulated to be one of the causes of the ageing process. In order to test whether pentane excretion is related to age, we measured breath pentane in 47 healthy subjects (ages 21-79). We also measured serum levels of the antioxidants tocopherol, retinol, lycopene, beta carotene, ascorbate and zinc. We found that pentane excretion significantly (P < 0.05, r = 0.32) increased with age. Of the six antioxidants measured, only lycopene decreased significantly (P < 0.05, r = -0.47) with age, however, this decline did not statistically correlate with pentane excretion. The remaining five antioxidants either remained stable or increased over the age range studied. We conclude that lipid peroxidation, as assessed by pentane excretion, increases with advancing age but that this increase is independent of dietary antioxidant levels.

The effect of lipid peroxides and superoxide dismutase on systemic lupus erythematosus: a preliminary study

Serum lipid peroxide (LPO) levels, superoxide dismutase (SOD) activity in peripheral blood erythrocytes, serum ANA, anti-dsDNA, and C3 were measured in 83 patients with systemic lupus erythematosus (SLE) and in 29 healthy controls. Compared to the controls, LPO levels were significantly increased in active SLE patients while SOD activity was markedly decreased. From the active phase to the inactive phase, a gradual decline in LPO levels and an increase in SOD activity were observed. There was a close correlation between LPO levels and disease activity or the parameters including ANA titers, anti-DNA titers, and C3 levels; a significant negative correlation was found between SOD activity and LPO levels or these parameters. Further, a marked difference in SOD activity was found in untreated active cases with and without nephritis. As the SLE patients improved, LPO levels gradually declined and SOD activity increased. The present study indicates that free radicals and resultantly formed lipid peroxide levels are higher in patients with SLE than those in normal persons, probably contributing to the production of autoantibodies, nephritis, and vasculitis of other organs, and that excessively generated free radicals may play an important role in the pathogenesis of SLE, which is possibly due to diminished SOD activity.

Essential oil phenyl propanoids. Useful as .OH scavengers?

In order to search for radical scavengers which could be used as raw materials for cosmetics, phenyl propanoids (eugenol, isoeugenol, dehydrodieugenol, dehydrodieugenol B and coniferyl aldehyde) were examined for their hydroxyl radical (.OH) scavenging ability. A Fenton system was used to produce .OH. In order to see scavenging by these phenyl propanoids, competition reactions between a spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and these phenyl propanoids for .OH were studied. The relative yield of the spin adduct of .OH (DMPO-OH) was measured by electron spin resonance spectroscopy. The approximate rate constants of the reactions between these phenyl propanoids and .OH estimated by measuring the reduced height of the ESR signals of DMPO-OH were found to be at least in the order of 10(9) M-1 s-1 (diffusion-controlled). Also, using the TBA tests, the reactions between .OH and several compounds reactive with .OH were investigated in the presence of the phenyl propanoids and it was found that the phenyl propanoids compete with such reactive compounds for .OH. These results indicate that these phenyl propanoids can be used as antioxidants for skin damage perhaps caused by .OH generated by UV-light.

Age-associated changes in antioxidants and antioxidative enzymes in rats

The antioxidative defence capacity was assessed in tissues from different groups of rats at 3, 12 and 24 months of age. It was observed that the levels of antioxidants, vitamin E and ascorbic acid decreased in serum without any changes in liver; whereas reduced glutathione showed lower levels in both serum and liver with advancing age. Antioxidative enzymes such as superoxide dismutase and catalase activities did not indicate appreciable changes in hepatic mitochondria, but were observed to point out divergent trends in post-mitochondrial supernatants, superoxide dismutase showed reduced activities and catalase activities enhanced with age.

Iodometric measurement of lipid hydroperoxides in human plasma

Many assay techniques have been used to measure lipid hydroperoxides in plasma, including absorbance of conjugated dienes and reactivity with thiobarbituric acid. Because these measurements are not specific for lipid hydroperoxides, we modified an exisiting iodometric method to correct for interfering phenomena and to provide a more specific measurement of the lipid hydroperoxide content of plasma. To ensure reproducible extraction of hydroperoxides from the many possible forms in plasma, the plasma was treated to hydrolyze enzymatically cholesterol ester, triglycerides, and phospholipids, and the nonesterified fatty acid peroxides were then extracted with ethyl acetate. Extracted lipids were reacted with potassium iodide in acetic acid and methylene chloride, and the resulting triiodide ion (I3-) was measured spectrophotometrically. Correction for nonoxidizing chromophores was made after back-titration of the triiodide ion to iodide with sodium thiosulfate and other non-peroxide oxidants were estimated by their resistance to reduction with glutathione peroxidase. Recovery of added hydroperoxide standards provided routine validations of the procedure's efficiency. The method indicated that insignificant amounts of hydroperoxide may be in the less polar lipids, but the total amount of lipid hydroperoxide esterfied in the plasma lipids of apparently healthy humans may be as much as 4.0 +/- 1.7 microM.

Chemistry and biochemistry of 4-hydroxynonenal, malonaldehyde and related aldehydes

Lipid peroxidation often occurs in response to oxidative stress, and a great diversity of aldehydes are formed when lipid hydroperoxides break down in biological systems. Some of these aldehydes are highly reactive and may be considered as second toxic messengers which disseminate and augment initial free radical events. The aldehydes most intensively studied so far are 4-hydroxynonenal, 4-hydroxyhexenal, and malonaldehyde. The purpose of this review is to provide a comprehensive summary on the chemical properties of these aldehydes, the mechanisms of their formation and their occurrence in biological systems and methods for their determination. We will also review the reactions of 4-hydroxyalkenals and malonaldehyde with biomolecules (amino acids, proteins, nucleic acid bases), their metabolism in isolated cells and excretion in whole animals, as well as the many types of biological activities described so far, including cytotoxicity, genotoxicity, chemotactic activity, and effects on cell proliferation and gene expression. Structurally related compounds, such as acrolein, crotonaldehyde, and other 2-alkenals are also briefly discussed, since they have some properties in common with 4-hydroxyalkenals.

Malondialdehyde (MDA) level in diabetic subjects. Relationship with blood glucose and glycosylated hemoglobin

The relationships between plasma malondialdehyde (MDA) and metabolic parameters in type I and II diabetic subjects have been studied at different levels of glycemic control. In 67 diabetics (20 type I, 47 type II, aged 53 +/- 1.2) and 40 healthy subjects (aged 47 +/- 1.75), triglycerides (TG), total cholesterol (CT) and C-HDL, fasting blood glucose (FBG), glycosylated hemoglobin (GHb) and MDA were measured. Diabetic population as a whole showed higher MDA plasma levels compared to controls, together with higher FBG, TG, GHb. MDA showed a significant correlation with both FBG and GHb, but was not correlated to plasma lipids. The patients with a poor metabolic control showed the highest plasma MDA concentrations, significantly different from the group with a better control: GHb less than 10% = MDA 2.77 +/- 0.28 nmol/ml - GHb greater than 10% = MDA 4.22 +/- 0.39 nmol/ml (z = 2.10, a less than 0.02); FBG less than 150 mg/dl = MDA 2.74 +/- 0.32 nmol/ml - FBG greater than 150 mg/dl = MDA 4.15 +/- 0.37 nmol/ml (z = 2.22, a less than 0.02). Glycemic equilibrium seemed to influence plasma MDA, increasing free radical production. This phenomenon probably occurred either because of enhanced glycosylation and platelet aggregation, or impairment of cellular antioxidant protective systems. The increased free radical production may play a role in the pathogenesis of metabolic vasculopathy.

Neutrophil chemotaxis, phagocytosis and parameters of reactive oxygen species in human aging: cross-sectional and longitudinal studies

To assess the effect of aging on neutrophil (PMN) functions and the parameters related to reactive oxygen species (ROS), we measured the following in blood samples from 166 asymptomatic aged individuals: PMN activities including chemotaxis, phagocytosis and generation of ROS; the activity of superoxide dismutase (SOD) of blood cell; and serum lipid peroxide levels. Compared with non-aged adults, the older individuals showed markedly attenuated PMN chemotaxis, and slightly elevated serum lipid peroxide levels. Other parameters were not significantly different between the two aged groups. In contrast both to the elderly group as a whole and to the subgroup 65 to 79 years old, the subjects over greater than or equal to 80 years old showed normal PMN chemotaxis and serum lipid peroxide levels, as defined by the young adult control group. Thirty-two subjects who entered the study at ages 69 to 72 years were followed with serial assays for seven years; twenty-one of these subjects died during this observation period. There was a striking and significant difference between the survivors and nonsurvivors with regard to PMN chemotaxis and serum lipid peroxide levels; even when asymptomatic upon initial examination, the nonsurvivors showed diminished PMN chemotaxis and elevated lipid peroxide levels. It seems from both the cross-sectional and longitudinal parts of our study that PMN chemotaxis and serum lipid peroxide levels correlate with survival to advanced age.

Glutathione metabolism of human vascular endothelial cells under peroxidative stress

Glutathione (GSH) plays an important role in the cellular defense against (per-)oxidative stress. The capacity of this cellular defense system may be related to the oxygen tension, cells are normally subjected to in vivo; therefore, we studied the de novo synthesis of glutathione, and the redox turnover under peroxidative stress, in human umbilical vein and artery endothelial cells (HUVEC, HUAEC) and human skin fibroblasts. De novo synthesis in these cell types was studied in vitro by measuring the time course of intracellular GSH recovery after depletion with diamide. For fibroblasts, the initial rate of de novo synthesis after GSH depletion was twice that of the endothelial cell strains. In the endothelial cells (HUVEC, HUAEC) the original intracellular GSH level is reached within 40 min. while in the same time span, the GSH level in fibroblasts returned to 75% of control level. The activity of the hexose monophosphate shunt (HMS) was determined under oxidative stress as a measure for the coupled redox turnover of intracellular GSH. Under control conditions the HMS in endothelial cells was twice as high as in fibroblasts. Cumene hydroperoxide (40 microM) induced a three-fold increase in HMS in both HUVEC and HUAEC, while fibroblasts exhibited an increase of 83%. During the same peroxidative stress, the intracellular GSH concentration of HUVEC, HUAEC and fibroblasts stayed at control level. So with respect to GSH metabolism there were no differences between the two endothelial cell strains. In comparison with the endothelial cells, the fibroblasts were less susceptible toward oxidative stress.(ABSTRACT TRUNCATED AT 250 WORDS)