Oxidative DNA base damage in lymphocytes of HIV-infected drug users

In the present study, we have studied the level of oxidative DNA base damage in lymphocytes of HIV-infected intravenous drug users (IDUs) and a seronegative control group. Chromatin was isolated from the lymphocytes and then analyzed by gas chromatography/isotope-dilution mass spectrometry with selectedion monitoring (GC/IDMS-SIM). Significantly greater levels of four oxidatively modified DNA bases were observed in chromatin samples from the symptomatic HIV-infected patients than in those from the seronegative patients. These were 5-hydroxyuracil, 5-hydroxycytosine, 8-hydroxyadenine and 8-hydroxyguanine. In the case of 5-hydroxyuracil and 8-hydroxyguanine, a statistically significant difference was also found between the control group and the asymptomatic HIV-positive patients. These results suggest that oxidative stress may play an important role in the pathogenesis of acquired immune deficiency syndrome (AIDS), and that administration of antioxidant drugs to HIV-infected patients may offer protection against AIDS-related carcinogenesis.     

Biochemical effects of pretreatment with vitamins E and C in rats submitted to intrastriatal hypoxanthine administration

We previously demonstrated that intrastriatal injection of hypoxanthine, the major metabolite accumulating in Lesch-Nyhan disease, inhibited Na+,K+-ATPase activity and induced oxidative stress in rat striatum. In the present study, we evaluated the action of vitamins E and C on the biochemical alteration induced by hypoxanthine administration on Na+,K+-ATPase, TBARS, TRAP, as well as on superoxide dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GPx) activities in striatum of adult rats. Animals received pretreatment with vitamins E and C or saline during 7 days. Twelve hours after the last injection of vitamins or saline, animals were divided into two groups: (1) vehicle-injected group and (2) hypoxanthine-injected group. For all parameters investigated in this research, animals were sacrificed 30 min after drug infusion. Results showed that pretreatment with vitamins E and C prevented hypoxanthine-mediated effects on Na+,K+-ATPase, TBARS and antioxidant enzymes (SOD, CAT and GPx) activities; however the reduction on TRAP was not prevented by these vitamins. Although extrapolation of findings from animal experiments to humans is difficult, it is conceivable that these vitamins might serve as an adjuvant therapy in order to avoid progression of striatal damage in patients affected by Lesch-Nyhan disease.     

Comparative study of oxidative stress and antioxidative markers in patients infected with Toxoplasma gondii

Recently, oxidative stress and antioxidative compounds have been described as potential biomarkers. However, there is no consensus on the most appropriate oxidative and antioxidative biomarkers for patients with Toxoplasma gondii. In the present study, we evaluated the levels of lipid, protein, DNA oxidative damage and antioxidants in samples from patients infected with T. gondii with and without ocular toxoplasmosis. The levels of MDA, TBARS, micronuclei, carbonyl, GSH, vitamin C and vitamin E were measured on samples from 8 patients positive for T. gondii antibodies with ocular toxoplasmosis (OT), 20 patients positive for T. gondii antibodies without ocular toxoplasmosis (non OT), and 12 healthy individuals negative for T. gondii antibodies. The levels of MDA, TBARS, carbonyl and micronuclei were significantly higher in non OT patients, while MDA and TBARS levels were lower in OT patients. In contrast, the antioxidative factors, GSH and vitamin E levels were significantly lower in non OT patients, while vitamin C was lower in non OT and OT patients. Additionally, non OT patients were indicated to be high producers of oxidative markers (TBARS, MDA, micronuclei and carbonyl), while control group was indicated to be high producer of antioxidative markers (GSH, vitamins C and E). However, OT patients were not found as high producers of oxidative nor antioxidative markers. Our results provide a starting point of possible markers to better understand the disease pathogenesis in patients infected with T. gondii. Additional studies are needed to clarify the potential contribution of oxidative and antioxidative markers in these patients population.     

Effect of Mild-to-Moderate Smoking on Viral Load,Cytokines, Oxidative Stress,and Cytochrome P450 Enzymes in HIV-Infected Individuals

Mild-to-moderate tobacco smoking is highly prevalent in HIV-infected individuals, and is known to exacerbate HIV pathogenesis. The objective of this study was to determine the specific effects of mild-to-moderate smoking on viral load, cytokine production, and oxidative stress and cytochrome P450 (CYP) pathways in HIV-infected individuals who have not yet received antiretroviral therapy (ART). Thirty-two human subjects were recruited and assigned to four different cohorts as follows: a) HIV negative non-smokers, b) HIV positive non-smokers, c) HIV negative mild-to-moderate smokers, and d) HIV positive mild-to-moderate smokers. Patients were recruited in Cameroon, Africa using strict selection criteria to exclude patients not yet eligible for ART and not receiving conventional or traditional medications. Those with active tuberculosis, hepatitis B or with a history of substance abuse were also excluded. Our results showed an increase in the viral load in the plasma of HIV positive patients who were mild-to-moderate smokers compared to individuals who did not smoke. Furthermore, although we did not observe significant changes in the levels of most pro-inflammatory cytokines, the cytokine IL-8 and MCP-1 showed a significant decrease in the plasma of HIV-infected patients and smokers compared with HIV negative non-smokers. Importantly, HIV-infected individuals and smokers showed a significant increase in oxidative stress compared with HIV negative non-smoker subjects in both plasma and monocytes. To examine the possible pathways involved in increased oxidative stress and viral load, we determined the mRNA levels of several antioxidant and cytochrome P450 enzymes in monocytes. The results showed that the levels of most antioxidants are unaltered, suggesting their inability to counter oxidative stress. While CYP2A6 was induced in smokers, CYP3A4 was induced in HIV and HIV positive smokers compared with HIV negative non-smokers. Overall, the findings suggest a possible association of oxidative stress and perhaps CYP pathway with smoking-mediated increased viral load in HIV positive individuals.     

Lycopene as a natural protector against gamma-radiation induced DNA damage, lipid peroxidation and antioxidant status in primary culture of isolated rat hepatocytes in vitro

The present study was designed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid, on gamma-radiation induced toxicity in cultured rat hepatocytes. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), ceruloplasmin, vitamins A, E, C and uric acid. The DNA damage was analysed by single cell gel electrophoresis (comet assay). The increase in the severity of DNA damage was observed with the increase in gamma-radiation dose (1, 2 and 4 Gy) in cultured rat hepatocytes. TBARS were increased significantly whereas the levels of GSH, vitamins C, E and A, ceruloplasmin, uric acid and antioxidant enzymes were significantly decreased in gamma-irradiated groups. The maximum damage to hepatocytes was observed at 4 Gy irradiation. Pretreatment with lycopene (1.86, 9.31 and 18.62 microM) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes increased significantly along with the levels of GSH, vitamins A, E, C, uric acid and ceruloplasmin. The maximum protection of hepatocytes was observed at 9.31 muM of lycopene pretreatment. Thus, our results show that pretreatment with lycopene offers protection against gamma-radiation induced cellular damage and can be developed as an effective radioprotector during radiotherapy.     

Lycopene as a natural protector against γ-radiation induced DNA damage,lipid peroxidation and antioxidant status in primary culture of isolated rat hepatocytes in vitro

The present study was designed to evaluate the radioprotective effect of lycopene, a naturally occurring dietary carotenoid, on γ-radiation induced toxicity in cultured rat hepatocytes. The cellular changes were estimated using lipid peroxidative indices like thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), ceruloplasmin, vitamins A, E, C and uric acid. The DNA damage was analysed by single cell gel electrophoresis (comet assay). The increase in the severity of DNA damage was observed with the increase in γ-radiation dose (1, 2 and 4 Gy) in cultured rat hepatocytes. TBARS were increased significantly whereas the levels of GSH, vitamins C, E and A, ceruloplasmin, uric acid and antioxidant enzymes were significantly decreased in γ-irradiated groups. The maximum damage to hepatocytes was observed at 4 Gy irradiation. Pretreatment with lycopene (1.86, 9.31 and 18.62 μM) showed a significant decrease in the levels of TBARS and DNA damage. The antioxidant enzymes increased significantly along with the levels of GSH, vitamins A, E, C, uric acid and ceruloplasmin. The maximum protection of hepatocytes was observed at 9.31 μM of lycopene pretreatment. Thus, our results show that pretreatment with lycopene offers protection against γ-radiation induced cellular damage and can be developed as an effective radioprotector during radiotherapy.     

Background level of 8-oxo-2'-deoxyguanosine in lymphocyte DNA does not correlate with the concentration of antioxidant vitamins in blood plasma.

Antioxidant vitamins, being effective free radical scavengers, can protect cellular DNA from oxidative damage. Therefore, in the present study we report on the relationship between basal level of 8-oxo-2'-deoxyguanosine in human lymphocyte DNA and the concentration of antioxidant vitamins (A, C and E). The average level of 8-oxo-2'-deoxyguanosine in lymphocytes of the studied group (15 males and 20 females) was 9.57 per 10(6) dG molecules. The endogenous level of ascorbic acid (vitamin C) in the plasma was, on average, 56.78 microM, while the mean concentrations of retinol (vitamin A) and alpha-tocopherol (vitamin E) were 1.24 uM and 25.74,uM, respectively. No correlations were found between individual 8-oxo-2 micro-deoxyguanosine levels in lymphocyte DNA and endogenous concentration of the vitamins.     

Breath alkanes as a marker of oxidative stress in different clinical conditions

We assessed oxidative stress in three different clinical conditions: smoking, human immunodeficiency virus (HIV) infection, and inflammatory bowel disease, using breath alkane output and other lipid peroxidation parameters such as plasma lipid peroxides (LPO) and malondialdehyde (MDA). Antioxidant micronutrients such as selenium, vitamin E, C, beta-carotene and carotenoids were also measured. Lipid peroxidation was significantly higher and antioxidant vitamins significantly lower in smokers compared to nonsmokers. Beta-carotene or vitamin E supplementation significantly reduced lipid peroxidation in that population. However, vitamin C supplementation had no effect. In HIV-infected subjects, lipid peroxidation parameters were also elevated and antioxidant vitamins reduced compared to seronegative controls. Vitamin E and C supplementation resulted in a significant decrease in lipid peroxidation with a trend toward a reduction in viral load. In patients with inflammatory bowel disease, breath alkane output was also significantly elevated when compared to healthy controls. A trial with vitamin E and C is underway. In conclusion, breath alkane output, plasma LPO and MDA are elevated in certain clinical conditions such as smoking, HIV infection, and inflammatory bowel disease. This is associated with lower levels of antioxidant micronutrients. Supplementation with antioxidant vitamins significantly reduced these lipid peroxidation parameters. The results suggest that these measures are good markers for lipid peroxidation.     

Effects of prenylated isoflavones osajin and pomiferin in premedication on heart ischemia-reperfusion

The present 15 days study was undertaken to evaluate the cardioprotective potential of the prenylated isoflavones osajin and pomiferin isolated from the infructences of Maclura pomifera, Moraceae, against ischemia-reperfusion induced injury in rat hearts as a model of antioxidant-based composite therapy. The study was performed on isolated, modified Langendorff-perfused rat hearts and the ischemia of heart was induced by stopping coronary flow for 30 min followed by 60 min of reperfusion (14 ml min(-1)). The Wistar rats were divided into four groups. The first treatment group received osajin (5 mg/kg/day in 0.5% Avicel); the second treatment group received pomiferin (5 mg/kg/day in 0.5% Avicel); the placebo group received only 0.5 Avicel; the last was an untreated control group. Biochemical indicator of oxidative damage-lipid peroxidation product malondialdehyde, antioxidant enzymes - superoxide dismutase, glutathione peroxidase, total antioxidant activity in serum and myocardium were evaluated. The effect of osajin and pomiferin on cardiac function, left ventricular end-diastolic pressure, left ventricular pressure and peak positive +dP/dt ischemia and reperfusion, also was examined. The results demonstrate that osajin and pomiferin attenuates the myocardial dysfunction provoked by ischemiareperfusion. This was confirmed by an increase in both antioxidant enzyme values and total antioxidant activity. The cardioprotection provided by osajin and pomiferin treatment results from the suppression of oxidative stress and this correlates with improved ventricular function.     

Effects of angiotensin II type 1 receptor blockade on the oxidative stress in spontaneously hypertensive rat tissues

The aim of this work was to investigate the production of oxidative damage in homogenized kidney, liver and brain of spontaneously hypertensive rats (SHR), as well as the involvement of angiotensin (Ang) II in this process. Groups of 12-week-old SHR and Wistar Kyoto rats (WKY) were given 10 mg/kg/day losartan in the drinking water during 14 days. Other groups of WKY and SHR without treatment were used as controls. The production of thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) were determined. No significant difference in TBARS was observed between untreated SHR or WKY rats; GSH content was lower in the liver but higher in the brain of SHR compared to WKY rats. In tissues from the SHR group, SOD and Gpx activities were reduced, whereas CAT activity was slightly increased in kidney. TBARS levels did not change in WKY rats after losartan administration, but were reduced in SHR liver and brain. Losartan treatment decreased GSH content in WKY kidney, but increased GSH in SHR liver. The activity of the antioxidant enzymes was not modified by losartan in WKY rats; however, their activities increased in tissues from treated SHR. The lower activity of antioxidant enzymes in tissues from hypertensive rats compared to those detected in normotensive controls, indicates oxidative stress production. Ang II seems to play no role in this process in normotensive animals, although AT1 receptor blockade in SHR enhances the enzymatic activity indicating that Ang II is implicated in oxidative stress generation in the hypertensive animals.     

CUPRAC colorimetric and electroanalytical methods determining antioxidant activity based on prevention of oxidative DNA damage

An unbalanced excess of oxygen/nitrogen species (ROS/RNS) can give oxidative hazard to DNA and other biomacromolecules under oxidative stress conditions. While the ‘comet’ assay for measuring DNA damage is neither specific nor practical, monitoring oxidative changes on individual DNA bases and other oxidation products needs highly specialized equipment and operators. Thus, we developed a modified CUPRAC (cupric ion reducing antioxidant capacity) colorimetric method to determine the average total damage on DNA produced by Fenton oxidation, taking advantage of the fact that the degradation products of DNA but not the original macromolecule is CUPRAC−responsive. The DNA−protective effects of water-soluble antioxidants were used to devise a novel antioxidant activity assay, considered to be physiologically more realistic than those using artificial probes. Our method, based on the measurement of DNA oxidative products with CUPRAC colorimetry proved to be 2 orders-of-magnitude more sensitive than the widely used TBARS (thiobarbituric acid-reactive substances) colorimetric assay used as reference. Additionally, the DNA damage was electrochemically investigated using pencil graphite electrodes (PGEs) as DNA sensor platform in combination with differential pulse voltammetry (DPV). The interaction of the radical species with DNA in the absence/presence of antioxidants was detected according to the changes in guanine oxidation signal.     

Antioxidant vitamin levels and glutathione peroxidase activity during ischemia/reperfusion in myocardial infarction

The consequences of increased oxidative stress, measured as the level of malondialdehyde (MDA) during ischemia/reperfusion, were studied in 48 patients in the acute phase of myocardial infarction (AMI) and a control group (21 blood donors). The serum levels of alpha-tocopherol and beta-carotene were followed. Immediately after the treatment onset the level of alpha-tocopherol started to decrease, reaching a plateau after 24 h. The consumption of beta-carotene was delayed by 90 min. Steady decline was detected during the whole time interval studied (48 h). Glutathione peroxidase (GPx) activity, as a representative of antioxidant enzymes, was estimated in whole blood. The influx of oxygenated blood was accompanied by a stimulation of GPx activity, which reached its maximum at the time of completed reperfusion. When comparing the AMI patients with the control group, the levels of MDA were found significantly increased, which indicates that oxidative stress is already increased during ischemia. Lower antioxidant levels found in the patients might either already be the result of vitamin consumption during ischemia or be a manifestation of their susceptibility to AMI. Monitored consumption of alpha-tocopherol and beta-carotene during reperfusion indicated that in the case of patients, whose level of antioxidant vitamins is below the threshold limit, a further substantial decrease of antioxidant vitamins during reperfusion could enhance the oxidative damage of the myocardium.     

Interaction of amoxicillin with DNA in human lymphocytes and H. pylori-infected and non-infected gastric mucosa cells

Amoxicillin is a penicillin derivative belonging to a group of beta-lactam antibiotics used in Helicobacter pylori eradication. Clinical application of amoxicillin is underlined by its antibacterial activity, but little is known about its interaction with DNA of human cells. Using the alkaline comet assay we investigated the genotoxicity of amoxicillin in human peripheral blood lymphocytes as well as in H. pylori-infected and non-infected human gastric mucosa cells. To assess the role of reactive oxygen species in the genotoxicity of amoxicillin we employed a set of antioxidant and free radical scavengers, including Vitamins C and E, melatonin and the nitrone spin trap N-tert-butyl-alpha-phenyl-nitrone (PBN). Amoxicillin-induced DNA damage was completely repaired after 60 min. The vitamins, melatonin and the spin trap decreased the extent of the damage. The cells exposed to amoxicillin and treated with endonuclease III and 3-methyladenine-DNA glycosylase II, the enzymes recognizing oxidized bases displayed greater extent of DNA damage than those not treated with these enzymes. H. pylori non-infected gastric mucosa cells exposed to hydrogen peroxide repaired their DNA in a 60 min incubation, but the infected cells were not able to do so. The action of DNA repair enzymes, the vitamins, melatonin and PBN indicated that amoxicillin-induced oxidative DNA damage. The drug did not induce DNA strand breaks in isolated pUC19 plasmid DNA. Our results suggest that amoxicillin can induce DNA damage in human lymphocytes and gastric mucosa cells and this effect may follow from the production of reactive oxygen species. Cellular activation of the drug is needed to induce DNA damage. Free radical scavengers and antioxidants may be used to assist H. pylori eradication with amoxicillin to protect DNA of the host cells. Our results suggest also that H. pylori infection may alter gastric mucosa cells response to DNA-damaging agents and in this way contribute to initiation/promotion of cancer transformation of these cells induced by external or internal carcinogens.     

Evaluation of oxidative DNA damage and antioxidant defense in patients with nasal polyps

Abstract

Objectives

The presence of inflammatory cells indicates the development of epithelial cell injury in nasal polyposis (NP) and the potential for production of high levels of reactive oxygen and nitrogen species. The aim of our study was to clarify the role of oxidative stress and antioxidant status in the deterioration accompanying NP.

Methods

Twenty patients (11 men) aged 47.2 ± 17.0 years with nasal polyps were included in the study. Twenty healthy subjects (7 men) aged 48.2 ± 15.3 years formed the control group. The erythrocyte activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and plasma nitric oxide (NO) concentrations were measured. An alkaline comet assay was used to determine the extent of blood lymphocyte DNA damage of oxidized purines as glicosylo-formamidoglicosylase (Fpg) sites, and oxidized pyrimidines as endonuclease III (Nth) sites.

Results

A significant increase of NO (P < 0.05) and non-significant decreases of SOD (P > 0.05), CAT (P > 0.05), and GPx (P > 0.05) were seen in NP patients compared to healthy controls. The level of blood lymphocyte oxidative DNA damage in NP patients was significantly higher compared to the control group (P = 0.01).

Discussion

The blood lymphocyte DNA damage level increased in patients with NP. Elevated DNA damage may be related to overproduction of reactive oxygen and nitrogen species and/or decreased antioxidant protection.     

Antioxidative and hypolipidemic effects of diosgenin, a steroidal saponin of yam (Dioscorea spp.), on high-cholesterol fed rats

Diosgenin (a steroidal saponin of yam) has long been used as a raw material for the industrial production of steroid drugs, and reported to have a hypocholesterolemic effect by suppressing cholesterol absorption and increasing cholesterol secretion. Oxidative stress has been suggested as a main risk factor in the development of atherosclerosis. The aim of this study is to investigate the possible hypolipidemic and antioxidative effect of diosgenin on rats fed with a high-cholesterol diet supplemented with either 0.1% or 0.5% diosgenin for 6 weeks. We measured the lipid profile in the plasma and liver, lipid peroxidation and antioxidative enzyme activities in the plasma, erythrocyte and gene expression of antioxidative enzymes in the liver, and the oxidative DNA damage in lymphocytes. Diosgenin showed a decrease in the plasma and hepatic total cholesterol levels, but increased the plasma high-density lipoprotein (HDL) cholesterol level. Erythrocyte TBARS and lymphocyte DNA damage measured by the comet assay were decreased in the diosgenin supplemented group. Furthermore, diosgenin feeding enhanced the resistance to lymphocyte DNA damage caused by an oxidant challenge with H(2)O(2). The antioxidative enzyme activities were also affected by diosgenin supplementation. Total superoxide dismutase (SOD) in the plasma and liver, glutathione peroxidase (GSH-Px) in erythrocytes, and catalase (CAT) in erythrocytes and liver were significantly increased in the 0.5% diosgenin group. The expression of antioxidative enzymes was up-regulated by diosgenin, the expression of GSH-Px being the highest in the 0.5% diosgenin group. These results suggest that diosgenin could be a very useful compound to control hypercholesterolemia by both improving the lipid profile and modulating oxidative stress.     

Ex-vivo purging of circulating monocytes results in immunovirologic improvement in partially HAART responder HIV-infected patients

AIDS pathogenesis results from a complex array of immune alterations which include, among others, changes in the pattern of cytokine production. Some monocyte-derived cytokines, like TNFalpha play a major role in HIV pathogenesis. TNFalpha transactivates HIV NF-kB thereby inducing viral replication, potentiates HIV replication in lymphomonocytes TNFalpha is one of the main factors of HIV-induced cachexia and might be involved in HAART-associated lipodystrophy. In addition, monocytes are infectable by HIV in vitro and infected monocytes can be recovered from the blood of HIV infected patients. For these reasons, we tested whether renewal of the pool of circulating monocytes by selective monocyte apheresis may improve the immune reconstitution which follows treatment with highly active anti-retrovirals (HAART). HIV-infected HAART receiving (> 1 year) patients who were either virologically non-responders (HIV-1 RNA >50,000 copies/ml) or immunologically non-responders (CD4 counts < 200) were treated with a novel monocyte apheresis device (G-1 Adacolumn). Plasma HIV viral load, proviral DNA and phenotypic and functional immunological analyses were performed. G-1 apheresis was well tolerated, not accompanied by adverse responses, and followed by clinical improvement. TNFalpha production was suppressed and CD4 T cell counts increased. In one G-1 patient with elevated HIV-1 proviral DNA a significant reduction (from 1,500 to 40 copies/10(5) cells) was observed. Neither immunologic nor virologic parameters were modified in the control patients who received HAART alone. Thus, purging of circulating monocytes by G-1 apheresis has a dramatic suppressive effect on TNFalpha production and is followed by both clinical and immunovirological improvement. G-1 apheresis should be considered in patients in whom HAART is only partially effective.     

AZT induces oxidative damage to cardiac mitochondria: protective effect of vitamins C and E

AZT (zidovudine) is a potent inhibitor of HIV replication and a major antiretroviral drug used for AIDS treatment. A major limitation in the use of AZT is the occurrence of severe side effects. The aim of this work was to test whether AZT causes oxidative damage to heart mitochondria and whether this can be prevented by supranutritional doses of antioxidant vitamins. An experimental animal model was used in which mice were treated with AZT for 35 days (10 mg/kg/day) in drinking water. Animals treated with antioxidant vitamins were fed the same diet as controls but supplemented with vitamins C (ascorbic acid, 10 g/ kg diet) and E (alpha-dl-tocopherol, 0.6 g/kg diet) for 65 days before sacrifice. This resulted in a daily intake of 1250 mg/kg/day (vitamin C) and 75 mg/kg/day (vitamin E). Cardiac mitochondrial DNA (mtDNA) of mice treated with AZT had over 120% more oxo-dG (8-oxo-7,8-dihydro-2'-deoxyguanosine, which is a biomarker of oxidative damage to DNA) in their mitochondrial DNA than untreated controls. AZT treatment also caused an increase in mitochondrial lipid peroxidation and an oxidation of mitochondrial glutathione. Dietary supplementation with supranutritional doses of the antioxidant vitamins C and E protected against these signs of mitochondrial oxidative stress. The oxidative effects of AZT are probably due to an increase in production of reactive oxygen species by mitochondria of AZT-treated animals, raising the possibility that oxidative stress may play an important role in the cardiotoxicity of AZT.     

Effects of crocin in reducing DNA damage,inflammation, and oxidative stress in multiple sclerosis patients: A double‐blind,randomized, and placebo‐controlled trial

Multiple sclerosis (MS) is an autoimmune disease in which the immune system attacks the nerve cells, resulting in neurological disorders. Oxidative stress, free radicals, and neuritis have important roles in MS pathogenesis. Here, we aim to evaluate the effect of crocin on inflammatory markers, oxidative damage, and deoxyribonucleic acid (DNA) damage in the blood of patients with MS. A total of 40 patients were divided into two groups, drug and placebo‐treated groups, using random assignment. Participants of the intervention and control groups received two crocin capsules or placebo per day for 28 days, respectively. Findings revealed a significant decrease in the level of important pathogenic factors in MS, including lipid peroxidation, DNA damage, tumor necrosis factor‐alpha, and interleukin 17 as well as a significant increase in the total antioxidant capacity in the serum of patients treated with crocin compared with the placebo group. Our results suggest the beneficial and therapeutic effects of crocin in MS.     

Determination of DNA damage induced by oxidative stress in hyperlipidemic patients.

In the present paper, we report data on the genotoxic properties of hydrogen peroxide in polymorphonuclear neutrophils (PMNLs) separated from normolipidemic and type II/a hyperlipidemic patients. In all, 15 hyperlipidemic patients (11 female, 4 male, mean age 54.6+/-10.25 years) were involved in the study, and 7 normolipidemic patients (5 female, 2 male, mean age 53.4+/-8.07 years) served as controls. Using the comet assay, there was a significant difference in the degree of DNA damage between the two groups. The visual score characteristic of the degree of DNA damage was 350.97+/-31.31 in the hyperlipidemic group, while it was 289.5+/-29.49 in the control group (P<0.001). In the hyperlipidemic patients, a positive correlation was found between the degree of DNA damage and the basic oxidation of PMNLs (r=0.517), and the superoxide anion production of the cells stimulated with phorbolmiristate acetate (PMA) (r=0.326) and formyl-Met-Leu-Phe (FMLP) (r=0.525) as well. There was a negative correlation between DNA damage and HDL-associated antioxidant paraoxonase (PON) activity (r=-0.469), and the PON/HDL ratio (r=-0.631). No correlation was found between the degree of DNA damage and the plasma concentration of nitric oxide (NO) (r=0.098) and thiobarbituric acid-reactive substances (TBARS) (r=0.061) in hyperlipidemic patients. Our results show that in hyperlipidemic patients there is an increase in lymphocyte DNA damage caused by oxidative stress when compared to normolipidemic individuals as demonstrated by comet assay. Decreased antioxidant capacity in hyperlipidemic patients may play a significant role in this process.