Antioxidant nutrients and chronic disease: use of biomarkers of exposure and oxidative stress status in epidemiologic research

Oxidation of lipid, nucleic acids or protein has been suggested to be involved in the etiology of several chronic diseases including cancer, cardiovascular disease, cataract, age-related macular degeneration and aging in general. A large body of research has investigated the potential role of antioxidant nutrients in the prevention of these and other chronic diseases. This review concentrates on the following antioxidant nutrients: beta-carotene and other carotenoids, vitamin E, vitamin C and selenium. The first part of the review emphasizes the utility of biological markers of exposure for these nutrients and the relationship to dietary intake data. The second part considers functional assays of oxidative stress status in humans including the strengths and limitations of various assays available for use in epidemiologic research. A wide variety of functional assays both in vivo and ex vivo, are covered, including various measures of lipid oxidation (thiobarbituric acid reactive substances, exhaled pentane/ethane, low-density lipoprotein resistance to oxidation, isoprostanes), DNA oxidation (oxidized DNA bases such as 8-OHdG, autoantibodies to oxidized DNA, modified Comet assay) and protein oxidation (protein carbonyls). Studies that have examined the effects of antioxidant nutrients on these functional markers are included for illustrative purposes. The review concludes with a discussion of methodologic issues and challenges for studies involving biomarkers of exposure to antioxidant nutrients and of oxidative stress status.     

锰对大鼠脑线粒体能量代谢及氧化损伤影响

目的 通过N-乙酰半胱氨酸(NAC)干预研究锰对大鼠脑纹状体和皮质线粒体能量代谢和氧化损伤的影响.方法 Wistar大鼠24只.按体重随机分成3组:对照组、MnCl2组、NAC预处理组,连续染毒21 d.取大鼠脑纹状体和皮质,梯度离心获得线粒体,测量顺乌头酸酶、线粒体复合体Ⅰ活性,丙二醛(MDA)、还原型谷胱甘肽(GSH)含量和线粒体膜电位.结果 与对照组比较,MnCl2组顺乌头酸酶[(18.64 nmol/(min.mg pro)]线粒体复合体Ⅰ((48.92nmol/(min.mg pro)]的活性显著降低;MDA含量[37.98nmol/(g pro)]显著升高,GSH含量(3.99μmol/(g pro)]显著降低;线粒体膜电位(荧光强度为25.54)显著降低(P＜0.05).与MnCl2组比较,NAC预处理组顺乌头酸酶[(22.95nmol/(min.mg pro))、线粒体复合体Ⅰ[(66.89nmol/(min.mg pro)]的活性显著升高;MDA含量[(31.44 nmol/(g pro)]显著降低,GSH含量(5.56μmol(g pro)]显著升高;线粒体膜电位(荧光强度为37.71)显著升高(P＜0.05).结论 锰可导致大鼠脑线粒体能量代谢障碍和氧化损伤;NAC预处理能有效预防锰所致大鼠脑线粒体能量代谢障碍和氧化损伤.     

Diet supplementation with iron augments brain oxidative stress status in a rat model of psychological stress

Objective

We investigated the influence of iron supplementation on brain oxidative stress and antioxidase activity in psychologically stressed rats.

Methods

Rats were maintained on diets with different iron doses for 1 wk, and all other constituents of the diet were equated exactly according to the AIN-93-G diet. At the end of the experimental period, rats were sacrificed and brains were collected. To evaluate the effect of iron consumption, serum iron, apparent iron absorption, levels of iron concentration, lipid peroxidation, reduced glutathione, and superoxide dismutase activities of brains were measured.

Results

Iron overload significantly elevated the level of iron content and malonaldehyde in rat brain, especially in the psychologically stressed group. Apparent iron absorption was decreased by increased iron supplementation in rats treated with psychological stress more than in control rats. Similarly, iron overload decreased superoxide dismutase activity and apparent iron absorption more significantly in psychologically stressed rats than in controls. Reduced glutathione level varied with diet, increasing in rats on a moderately high-iron diet but decreasing in rats on a extremely high-level iron diet.

Conclusion

These results demonstrated that iron overload augments brain oxidative stress status and aggravates the decrease of apparent iron absorption in a rat model of psychological stress.     

Iron status and oxidative stress biomarkers in adults: A preliminary study

ObjectiveAlthough essential to many vital processes, iron catalyzes reactions that produce reactive oxygen species, which are associated with the increased risk of non-communicable chronic diseases and precocious aging. This study investigated whether ferritin, hemoglobin concentration, and dietary iron consumption are related to oxidative stress biomarkers in adults.MethodsData were collected from 134 allegedly healthy subjects >18 y of age who were randomly selected to participate in a cross-sectional study as part of the pilot project Prevalence of Risk Factors for Non-communicable Chronic Diseases in the Federal District, Brazil (VIVA Saúde-DF). Serum ferritin, malondialdehyde (MDA) and protein carbonyl concentrations, hemoglobin, and dietary iron consumption were analyzed.ResultsA weak positive correlation (r = 0.189, P = 0.032) and association (P = 0.046) was observed for serum ferritin and MDA. Hemoglobin concentrations were positively associated with serum MDA (P = 0.040). Dietary iron intake and serum protein carbonyl concentrations showed a weak positive correlation (r = 0.173, P = 0.046) for all subjects. Iron intake by women was positively associated with serum protein carbonyl (P = 0.03). A lower serum MDA concentration was found in ferritin-deficient subjects (P = 0.015) and men with anemia (P = 0.011).ConclusionThese results suggest that low levels of iron may reduce oxidative stress.     

Effects of protein malnutrition on oxidative status in rat brain

OBJECTIVES: This study evaluated the effects of protein malnutrition on oxidative status in rat brain areas. METHODS: We investigated various parameters of oxidative status, free radical content (dichlorofluorescein formation), indexes of damage to lipid (thiobarbituric acid-reactive substances assay), and protein damage (tryptophan and tyrosine content) in addition to total antioxidant reactivity levels and antioxidant enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase in different cerebral regions (cortex, hippocampus, and cerebellum) from rats subjected to prenatal and postnatal protein malnutrition (control 25% casein and protein malnutrition 7% casein). RESULTS: Protein malnutrition altered various parameters of oxidative stress, especially damage to macromolecules. Free radical content was unchanged by protein malnutrition. There was an increase in levels of thiobarbituric acid-reactive substances, the index of lipid peroxidation, in the cerebellum and cerebral cortex (P < 0.05) from protein-malnourished rats. Moreover, significant decreases in tryptophan and tyrosine in all tested brain structures (P < 0.05) were observed. Catalase activity was significantly decreased in the cerebellum (P < 0.05). In addition, a significant decrease in total antioxidant reactivity levels (P < 0.05) was observed in the cerebral cortex from protein-malnourished rats. CONCLUSIONS: The present data indicated that protein malnutrition increased oxidative damage to lipids and proteins from the studied brain areas. These results may be an indication of an important mechanism for changes in brain development that are caused by protein malnutrition.     

Effects of lead exposure on oxidative stress biomarkers and plasma biochemistry in waterbirds in the field

Medina lagoon in Andalusia has one of the highest densities of spent lead (Pb) shot in Europe. Blood samples from waterbirds were collected in 2006–2008 to measure Pb concentration (PbB), δ-aminolevulinic acid dehydratase (ALAD), oxidative stress biomarkers and plasma biochemistry. PbB above background levels (>20 μg/dl) was observed in 19% (n=59) of mallards (Anas platyrhynchos) and in all common pochards (Aythya ferina) (n=4), but common coots (Fulica atra) (n=37) and moorhens (Gallinula chloropus) (n=12) were all <20 μg/dl. ALAD ratio in mallards and coots decreased with PbB levels >6 μg/dl. In mallards, an inhibition of glutathione peroxidase (GPx) and an increased level of oxidized glutathione (oxGSH) in red blood cells (RBC) were associated with PbB levels >20 μg/dl. In coots, PbB levels were negatively related to vitamin A and carotenoid levels in plasma, and total glutathione in RBCs; and positively related with higher superoxide dismutase and GPx activities and % oxGSH in RBCs. Overall, the results indicate that previously assumed background levels of PbB for birds need to be revised.     

Effects of short-term moderate alcohol administration on oxidative stress and nutritional status in healthy males

The effects of moderate amounts of different alcoholic beverages on oxidative stress and nutritional parameters were investigated in 40 healthy subjects. Ethanol 40 g/day was administered at the two main meals for 30 days by beer (group A), wine (group B) or spirit (group C); controls (group D) maintaned abstinence. Malondyaldeide (MDA), adenosine-triphosphate (ATP), reduced-glutathione (GSH), E-vitamin and nutritional status were evaluated at the start (T0) and the end (T1) of the study. At T1 controls did not present significant changes in the assessed parameters, while a significant increase of malondyaldeide (MDA) and a significant decrease of reduced-glutathione and E-vitamin in group A, B and C and of ATP in group C were observed. Fat mass (FM) increased slightly in group A and B and decreased in group C. Ethanol decreased antioxidant parameters and increased lipoperoxidation parameters. However some of these changes appeared attenuated when ethanol was consumed in beer or wine. Finally, short-term moderate ethanol intake appeared to influence the FM, although it was not able to significantly affect nutritional or body composition.     

Melatonin reduces oxidative stress induced by chronic exposure of microwave radiation from mobile phones in rat brain

PURPOSE: The aim of the study was to evaluate the intensity of oxidative stress in the brain of animals chronically exposed to mobile phones and potential protective effects of melatonin in reducing oxidative stress and brain injury. MATERIALS AND METHODS: Experiments were performed on Wistar rats exposed to microwave radiation during 20, 40 and 60 days. Four groups were formed: I group (control)- animals treated by saline, intraperitoneally (i.p.) applied daily during follow up, II group (Mel)- rats treated daily with melatonin (2 mg kg(-1) body weight i.p.), III group (MWs)- microwave exposed rats, IV group (MWs + Mel)- MWs exposed rats treated with melatonin (2 mg kg(-1) body weight i.p.). The microwave radiation was produced by a mobile test phone (SAR = 0.043-0.135 W/kg). RESULTS: A significant increase in the brain tissue malondialdehyde (MDA) and carbonyl group concentration was registered during exposure. Decreased activity of catalase (CAT) and increased activity of xanthine oxidase (XO) remained after 40 and 60 days of exposure to mobile phones. Melatonin treatment significantly prevented the increase in the MDA content and XO activity in the brain tissue after 40 days of exposure while it was unable to prevent the decrease of CAT activity and increase of carbonyl group contents. CONCLUSION: We demonstrated two important findings; that mobile phones caused oxidative damage biochemically by increasing the levels of MDA, carbonyl groups, XO activity and decreasing CAT activity; and that treatment with the melatonin significantly prevented oxidative damage in the brain.     

Antioxidant vitamin status in high exposure to oxidative stress in competitive athletes

We conducted a cross-sectional study in 118 well-trained athletes to investigate 'high exposure' to sub-deficient antioxidant status, and consequently to oxidative damage, in relation to estimated daily energy expenditure (EE) and dietary antioxidant intake. Subjects completed 7 d food and activity records. Blood samples were obtained on day 8. Of the athletes 81, 60 and 43% had intakes of vitamins E, C and beta-carotene below two-thirds of the French RDA respectively, which is adjusted for EE (FRDAa). The deficit in vitamin E intake was positively correlated with EE (r 0.51, P<0.0001). All the athletes had normal plasma vitamins E and C and 14% had marginal plasma beta-carotene. Plasma thiobarbituric acid-reactive substances (TBARS) did not increase with increased EE. As evidenced by ANOVA, EE-induced vitamin C intakes increased and consequently led to increased plasma ascorbic acid concentrations. In male athletes, plasma total carotenoids were negatively correlated with plasma TBARS concentrations (r -0.31, P<0.006). The relationship between vitamin C intakes and plasma concentrations was logarithmic (r 0.59, P< 0.0001). To summarize, it is not clear whether vitamin E requirements are overestimated with reference to EE in the FRDAa. Daily requirements for vitamin C do not exceed 200 mg. Our present results could be interpreted as meaning that carotenoids play a protective role as exogenous antioxidants. Carotenoid intakes in athletes must be considered carefully.     

母鼠围产期铅暴露对仔鼠不同脑区POU域蛋白表达的影响

目的探讨POU域蛋白在铅的神经毒性机制中的作用。方法受孕雌性大鼠从妊娠第15天开始经饮水染铅(对照饮蒸馏水,试验组醋酸铅低0.5g L、中1.0g L、高2.0g L),至仔鼠出生后21日断乳为止。分别取21日龄仔鼠大脑皮层、海马、小脑部位组织制作冰冻切片,采用免疫组织化学方法测定不同脑区的Oct2和Brn3a蛋白表达水平。结果显微图像分析表明,染铅组脑组织皮层、海马及小脑的Oct2和Brn3a蛋白表达的阳性面积比[Aa(%)]、平均灰度与对照组相比其差异有不同程度的显著性(P<0.05或P<0.01),并呈剂量依赖性的变化。染铅组Oct2表达高于对照组,而Brn3a表达低于对照组。结论POU域蛋白作为转录调节因子参与了铅对学习记忆损害的神经毒性过程。     

Mangiferin decreases inflammation and oxidative damage in rat brain after stress

Purpose

Stress exposure elicits neuroinflammation and oxidative damage in brain, and stress-related neurological and neuropsychiatric diseases have been associated with cell damage and death. Mangiferin (MAG) is a polyphenolic compound abundant in the stem bark of Mangifera indica L. with antioxidant and anti-inflammatory properties in different experimental settings. In this study, the capacity of MAG to prevent neuroinflammation and brain oxidative damage induced by stress exposure was investigated.

Methods

Young–adult male Wistar rats immobilized during 6?h were administered by oral gavage with increasing doses of MAG (15, 30, and 60?mg/Kg), respectively, 7?days before stress.

Results

Prior treatment with MAG prevented all of the following stress-induced effects: (1) increase in glucocorticoids (GCs) and interleukin-1β (IL-1β) plasma levels, (2) loss of redox balance and reduction in catalase brain levels, (3) increase in pro-inflammatory mediators, such as tumor necrosis factor alpha TNF-α and its receptor TNF-R1, nuclear factor-kappa B (NF-κB) and synthesis enzymes, such as inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), (4) increase in lipid peroxidation.

Conclusions

These multifaceted protective effects suggest that MAG administration could be a new therapeutic strategy in neurological/neuropsychiatric pathologies in which hypothalamic/pituitary/adrenal (HPA) stress axis dysregulation, neuroinflammation, and oxidative damage take place in their pathophysiology.     

江苏省部分地区婴幼儿碘营养状况及影响因素分析

【目的】 调查江苏省婴幼儿碘营养状况及影响因素,为本地区婴幼儿合理的碘摄取提供参考意见。 【方法】 采用分层随机抽样的方法,收集2 329名婴幼儿,检测尿碘浓度,询问并填写调查表,体格测量,分析尿碘水平及影响因素。 【结果】 1)江苏省5地区婴幼儿尿碘浓度四分位数间距(Q75~Q25)为250~100μg/L,尿碘中位数(MUI)为200 μg/L;尿碘浓度(UIC)＜100μg/L的比例为12.2%,UIC＞300 μg/L者占5.2%。2)不同月龄尿碘分布情况存在差异(χ²=19.870,P<0.05),不同地区尿碘分布情况存在差异(χ²=60.355,P<0.001)。3)Logistic回归分析显示:尿碘值可能与儿童月龄、居住地区及添加食盐有关,与父母文化程度无关。 【结论】 江苏省五地区婴幼儿平均碘营养状况处于适宜水平,仍存在碘缺乏和碘过量的现象;不同地区尿碘分布情况不同,城市尤以南京市婴幼儿碘缺乏和碘过量比例较高。     

乐果对大鼠大脑分区多巴胺神经递质的影响

目的观察乐果染毒对大鼠大脑分区单胺类神经递质多巴胺(DA)及其代谢物(DOPAC)浓度变化的影响。方法104只雄性SD大鼠随机分为对照组(生理盐水)和乐果染毒低(38.9mg/kg)、中(83.7mg/kg)、高(180.0mg/kg)3个剂量组,腹腔一次注射染毒,给药后0.5、2、8和24h断头处死并分离脑组织(大脑皮层、纹状体、海马、脑干和小脑5部分)。用正丁醇、正庚烷、高氯酸、三氯甲烷处理脑组织样品,用高效液相色谱电化学检测法检测。结果不同时程的染毒组(低、中、高剂量组)大脑DA浓度及其代谢物DOPAC与对照组相比差异均有显著性(P<0.05)。DA及其代谢物DOPAC在纹状体分别增加了28%~122%、89%~538%;DA在其它分区变化差异没有显著性。DOPAC在大脑皮层有的剂量和时程增加了50%~72%、有的剂量和时程减少了31%~51%;在海马差异没有显著性;在脑干有的剂量和时程增加了4%~102%、有的剂量和时程减少了10%~16%;在小脑有的剂量和时程增加了6%~39%、有的剂量和时程减少了6%~23%。DA和DOPAC浓度在不同时程的低、中、高剂量组间差异均有显著性(P<0.05)。结论DA和DOPAC浓度有随染毒剂量和时程的增加而增加的趋势,存在剂量-效应和时程-效应关系。因此乐果的中毒存在非胆碱能机制,多巴胺类能机制。     

Air pollution and circulating biomarkers of oxidative stress

Chemical components of air pollutant exposures that induce oxidative stress and subsequent inflammation may be partly responsible for associations of cardiovascular morbidity and mortality with airborne particulate matter and combustion-related pollutant gasses. However, epidemiologic evidence regarding this is limited. An exposure-assessment approach is to measure the oxidative potential of particle mixtures because it is likely that hundreds of correlated chemicals are involved in overall effects of air pollution on health. Oxidative potential likely depends on particle composition and size distribution, especially ultrafine particle concentration, and on transition metals and certain semi-volatile and volatile organic chemicals. For health effects, measuring systemic oxidative stress in the blood is one feasible approach, but there is no universal biomarker of oxidative stress and there are many potential target molecules (lipids, proteins, DNA, nitric oxide, etc.), which may be more or less suitable for specific study goals. Concurrent with the measurement of oxidative stress, it is important to measure gene and/or protein expression of endogenous antioxidant enzymes because they can modify relations between oxidative stress biomarkers and air pollutants. Conversely, the expression and activities of these enzymes are modified by oxidative stress. This interplay will likely determine the observed effects of air pollutants on systemic inflammatory and thrombotic mediators and related clinical outcomes. Studies are needed to assess the reliability and validity of oxidative stress biomarkers, evaluate differences in associations between oxidative stress biomarkers and various pollutant measurements (mass, chemical components, and oxidative potential), and evaluate impacts of antioxidant responses on these relations.