Lecithinized copper, zinc-superoxide dismutase ameliorates prolonged hypoxia-induced injury of cardiomyocytes

Recent studies have suggested that prolonged hypoxia results in increased production of reactive oxygen species in cardiomyocytes, which leads to apoptosis of these cells. We previously showed that lecithinized recombinant human copper, zinc-superoxide dismutase (rhSOD) showed increased bioavailability through greater membrane affinity and a longer half-life than unmodified SOD. The purpose of this study was to investigate whether lecithinized SOD plays a protective role against hypoxic injury in cardiomyocytes. Cultured rat cardiomyocytes incubated with lecithinized SOD (100 U/ml), unmodified SOD (100 U/ml), or vehicle alone were subjected to hypoxia for up to 72 h. Lecithinized SOD, but not unmodified SOD, was successfully delivered intracellularly, which was verified by Western blot and confocal laser-scanning microscopy. Treatment of cells with lecithinized SOD significantly suppressed hypoxia-induced cell damage. Since lecithinized SOD also suppressed hypoxia-induced DNA fragmentation, the improved cell survival provided by lecithinized SOD is thought to be mediated by its antiapoptotic effect. In summary, lecithinization resulted in a facilitated rhSOD delivery into cultured cardiomyocytes, which reduced mortality of cardiomyocytes exposed to prolonged hypoxia.     

Superoxide dismutase production by Isaria fumosorosea on metals and its role in stress tolerance and fungal virulence

Superoxide dismutase (SOD) is an anti-oxidant enzyme which also plays a role in fungal virulence. The present study was conducted to elucidate its role in fungal infection and stress tolerance of entomopathogenic fungi, Isaria fumosorosea. SOD activity of I. fumosorosea conidia differed significantly on the growth medium supplemented with different metal compounds. The use of Cu + Zn proved to be the most active inducer of SOD activity. Cu + Zn treatment enhanced the fungal tolerance to oxidative stress generated by menadione in the medium (0–3 mM) as evaluated by colony growth. The conidial tolerance to UV-B radiation and heat was evaluated by assays of spore germination. Conidia produced on cultures with Cu + Zn were more tolerant to UV-B and thermal stress as well as exhibiting a higher rate of virulence against P. xylostella larvae. Our study highlights that SOD contributes significantly to the virulence and stress tolerance of I. fumosorosea and reveals possible means to improving field persistence and efficacy of a fungal formulation by manipulating the antioxidant enzymes of fungal pathogens.     

Alterations in Antioxidant Enzymes During Aging in Humans

The oxidative stress theory of aging offers the best mechanistic elucidation of the aging phenomenon and other age-related diseases. The susceptibility of an individual depends on the antioxidant status of the body. In humans, the antioxidant system includes a number of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT), nonenzymatic antioxidants such as glutathione (GSH), protein –SH, ascorbic acid, and uric acid, and dietary antioxidants. Antioxidant enzymes form the first line of defense against reactive oxygen species. In an earlier report, we showed that the plasma antioxidant potential in humans decreases as a function of age and that there are compensatory mechanisms operating in the body which are induced to maintain the antioxidant capacity during aging. In the present study, we report the relationship between human aging and antioxidant enzymes SOD and CAT; we also correlate the activity of these enzymes with the antioxidant capacity of the plasma. Our results show a significantly higher plasma SOD and CAT activity in older individuals than in younger individuals. The induction in activity of SOD and CAT during human aging may be a compensatory response of the individual to an increased oxidative stress.     

食用菌体内抗氧化酶活性影响因素的研究进展

食用菌的菌丝和子实体在正常生长发育中会产生活性氧,但是在环境胁迫下或者贮藏运输中活性氧会大量增加,打破了活性氧的平衡,必须依靠抗氧化酶系对抗其有害作用。介绍了抗氧化酶的种类及其作用,综述了食用菌不同部位、不同发育阶段等自身因素,及温度、金属离子、采后保鲜技术等外界环境因素对抗氧化酶活性的影响,并对食用菌抗氧化酶研究前景进行展望。     

Protective effect of butin against hydrogen peroxide-induced apoptosis by scavenging reactive oxygen species and activating antioxidant enzymes

The antioxidant property of butin was investigated for cytoprotective effect against H(2)O(2)-induced cell damage. This compound showed intracellular reactive oxygen species (ROS) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, inhibition of lipid peroxidation, and DNA damage. This radical scavenging activity of butin protected cell damage exposed to H(2)O(2). Also, butin reduced the apoptotic cells induced by H(2)O(2), as demonstrated by the decreased DNA fragmentation, apoptotic body formation, and caspase 3 activity. In addition, butin restored the activity and protein expression of cellular antioxidant enzymes, superoxide dismutase (SOD), and catalase (CAT) in H(2)O(2)-treated cells. Taken together, these findings suggest that butin protected cells against H(2)O(2)-induced cell damage via antioxidant property.     

Lack of the effect of superoxide dismutase and catalase on Na+,K+-ATPase activity in stunned rabbit hearts

Reactive oxygen species (ROS) have been implicated in the mechanism of postischemic contractile dysfunction, known as myocardial stunning. In this study, we examined protective effects of antioxidant enzymes, superoxide dismutase (SOD) and catalase, against ischemia/reperfusion-induced cardiac dysfunction and inhibition of Na+,K+-ATPase activity. Isolated Langendorff-perfused rabbit hearts were subjected to 15 min of global normothermic ischemia followed by 10 min reperfusion. The hearts treated with SOD plus catalase did not show significant recovery of left ventricular (LV) end-diastolic pressure compared with untreated ischemic reperfused hearts. Treatment with antioxidants had no protective effects on developed LV pressure or its maximal positive and negative first derivatives (+/-LVdP/dt). Myocardial stunning was accompanied by significant loss in sarcolemmal Na+,K+-ATPase activity and thiol group content. Inhibition of enzyme activity and oxidation of SH groups were not prevented by antioxidant enzymes. These results suggest that administration of SOD and catalase in perfusate do not protect significantly against cardiac dysfunction in stunned rabbit myocardium.     

Superoxide dismutase restores eNOS expression and function in resistance pulmonary arteries from neonatal lambs with persistent pulmonary hypertension

Endothelial nitric oxide (NO) synthase (eNOS) expression and activity are decreased in fetal lambs with persistent pulmonary hypertension (PPHN). We sought to determine the impact of mechanical ventilation with O(2) with or without inhaled NO (iNO) or recombinant human SOD (rhSOD) on eNOS in the ductal ligation model of PPHN. PPHN lambs and age-matched controls were ventilated with 100% O(2) for 24 h alone or combined with 20 ppm iNO continuously or a single dose of rhSOD (5 mg/kg) given intratracheally at delivery. In 1-day spontaneously breathing lambs, eNOS expression in resistance pulmonary arteries increased relative to fetal levels. eNOS expression increased in control lambs ventilated with 100% O(2), but not in PPHN lambs. Addition of iNO or rhSOD increased eNOS expression and decreased generation of reactive oxygen species (ROS) in PPHN lambs relative to those ventilated with 100% O(2) alone. However, only rhSOD restored eNOS function, increased tetrahydrobiopterin (BH(4)), a critical cofactor for eNOS function, and restored GTP cyclohydrolase I expression in isolated vessels and lungs from PPHN lambs. These data suggest that ventilation of PPHN lambs with 100% O(2) increases ROS production, blunts postnatal increases in eNOS expression, and decreases available BH(4) in PPHN lambs. Although the addition of iNO or rhSOD diminished ROS production and increased eNOS expression, only rhSOD improved eNOS function and levels of available BH(4). Thus therapies designed to decrease oxidative stress and restore eNOS coupling, such as rhSOD, may prove useful in the treatment of PPHN in newborn infants.     

烟草气孔特性、抗氧化酶活性与臭氧伤害的关系

 2001～2002连续两年在大田生产条件下研究了10个烤烟基因型气孔密度和气孔导度的变异情况及其与抗臭氧伤害的关系;2002年在控制条件下采用低温加臭氧的方法处理烟草植株,研究分析了烟草叶片遭受臭氧伤害后抗氧化酶活性的变化及其与抗臭氧伤害的关系。结果表明：烤烟不同基因型对臭氧伤害的抗性存在显著的差异。烟草叶片下表皮气孔密度和气孔导度与臭氧伤害引起的气候斑点病具有相关关系,在烟株下部叶中,其相关性分别达到显著（R2001＝0.68,R2002＝0.65）和极显著水平（R2001＝0.87,R2002＝0.80）。因此,下部叶气孔密度和气孔导度可以作为抗病育种的选择指标。在控制条件下的试验结果表明：只有低温加臭氧复合因子才能诱发烟草叶片产生臭氧伤害症状。烟草叶片低温下遭遇臭氧伤害后,超氧化物歧化酶（SOD）活性升高,升幅与气候斑点病病情指数负相关,过氧化氢酶（CAT）活性略有升高,过氧化物酶（POD）活性急剧下降。抗性较差的烟草基因型抗氧化酶反应不敏感,臭氧伤害症状严重,抗性较强的烟草基因型抗氧化酶反应敏感,臭氧伤害症状较轻。低温和臭氧同时作用明显影响了活性氧清除系统,致使系统中酶活性比例失调,POD活性急剧下降,可能是烟草叶片产生臭氧伤害的原因之一,SOD和CAT活性升高对消除臭氧伤害具有一定的防御作用。     

Differential Response of the Catalase,Superoxide Dismutase and Glycerol-3-phosphate Dehydrogenase to Different Environmental Stresses in <Emphasis Type="Italic">Debaryomyces nepalensis</Emphasis> NCYC 3413

The effect of salt, pH, and temperature stress on the cellular level of antioxidant enzymes, catalase and superoxide dismutase (SOD) and glycerol-3-phosphate dehydrogenase (G3PDH) was studied in Debaryomyces nepalensis NCYC 3413, a halotolerant yeast. The catalase activity increased in different phases, while SOD and G3PDH activities declined in late stationary phase. A significant increase in SOD activity was observed under different stress as compared to control. Salt and temperature stress enhanced the catalase activity where as it was suppressed by pH stress. G3PDH level increased with salt stress, however, no significant change was observed under pH and temperature stress. The observations recorded in this investigation suggested that D. nepalensis has an efficient protective mechanism of antioxidant enzymes and G3PDH against salt, pH, and temperature stresses.     

Induction of manganese superoxide dismutase in cultured human trophoblast during in vitro differentiation.

The antioxidant responses of human cell differentiation and membrane fusion are not known and may be important in understanding cellular response to injury in the human placenta. We studied the regulation of antioxidant enzymes in human trophoblasts which differentiate from mononucleated cellular trophoblasts to synctium in vivo and in culture. We characterized morphological and biochemical differentiation of cultured trophoblasts from term placenta in the presence or absence of serum, on different growth surfaces, and with a range of plating densities. Culture of cellular trophoblasts consistently and transiently induced the mRNAs of the mitochondrial antioxidant manganese superoxide dismutase (Mn SOD) but not the mRNAs for the antioxidant enzymes copper zinc SOD or catalase. Fibrin and type I collagen substrates modulated only the expression of the placental specific proteins, human chorionic gonadotropin, and human placental lactogen. Both Mn SOD induction and terminal differentiation, as reflected by human chorionic gonadotropin expression, were dependent on trophoblastic plating density. Increased levels of a smaller Mn SOD mRNA species correlated temporally with an increase in Mn SOD enzyme activity in cultured trophoblasts. These results demonstrate that Mn SOD gene expression and enzyme activity precede or are coordinately regulated with morphological and biochemical trophoblastic differentiation.     

Alterations of the levels of primary antioxidant enzymes in different grades of human astrocytoma tissues

Malignant astrocytoma is the most commonly occurring brain tumour in humans. Oxidative stress is implicated in the development of cancers. Superoxide dismutase 2 (SOD2) was found to exert tumour suppressive effect in basic research, but increased SOD2 protein level was associated with higher aggressiveness of human astrocytomas. However, studies reporting alterations of antioxidant enzymes in human astrocytomas often employed less accurate methods or included different types of tumours. Here we analysed the mRNA levels, activities, and protein levels of primary antioxidant enzymes in control brain tissues and various grades of astrocytomas obtained from 40 patients. SOD1 expression, SOD1 activity, and SOD1 protein level were lower in Grade IV astrocytomas. SOD2 expression was lower in low-grade (Grades I and II) and Grade III astrocytomas than in controls, but SOD2 expression and SOD2 protein level were higher in Grade IV astrocytomas than in Grade III astrocytomas. Although there was no change in SOD2 activity and a lower activity of citrate synthase (CS), the MnSOD:CS ratio increased in Grade IV astrocytomas compared with controls and low-grade astrocytomas. Furthermore, SOD1 activity, CS activity, SOD1 expression, GPX4 expression, and GPX4 protein level were inversely correlated with the malignancy, whereas catalase activity, catalase protein, SOD2 protein level, and the SOD2:CS ratio were positively correlated with the degree of malignancy. Lower SOD2:CS ratio was associated with poor outcomes for Grade IV astrocytomas. This is the first study to quantify changes of various primary antioxidant enzymes in different grades of astrocytomas at different levels concurrently in human astrocytomas.     

Antioxidant responses of the Mediterranean mussel, Mytilus galloprovincialis, to environmental variability of dissolved oxygen

Physiological responses of Mytilus galloprovincialis against environmental dissolved oxygen partial pressure (pO(2)) variation were studied in terms of the modulated induction of the main antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (GPX). Field in vivo studies were performed at two sites of the Lagoon of Venice, characterized by different aquatic environmental conditions implying different pO(2). SOD and GPX are more active in gills, and their complementary role is discussed. CAT is more active in the digestive gland, where the enzyme dismutates H(2)O(2) derived from divalent reduction of O(2) performed by various oxidases in peroxisomes. Antioxidant enzyme activities are correlated with water dissolved oxygen (DO), especially in the gills. This tissue, because of its anatomical localization and its physiological role, responds to DO variations modulating the induction of the antioxidant enzymes as a protection mechanism against potential toxicity due to increases in ROS formation.     

Mechanism of Cu,Zn-superoxide dismutase activation by the human metallochaperone hCCS

The mechanism for copper loading of the antioxidant enzyme copper, zinc superoxide dismutase (SOD1) by its partner metallochaperone protein is not well understood. Here we show the human copper chaperone for Cu,Zn-SOD1 (hCCS) activates either human or yeast enzymes in vitro by direct protein to protein transfer of the copper cofactor. Interestingly, when denatured with organic solvents, the apo-form of human SOD1 cannot be reactivated by added copper ion alone, suggesting an additional function of hCCS such as facilitation of an active folded state of the enzyme. While hCCS can bind several copper ions, metal binding studies in the presence of excess copper scavengers that mimic the intracellular chelation capacity indicate a limiting stoichiometry of one copper and one zinc per hCCS monomer. This protein is active and unlike the yeast protein, is a homodimer regardless of copper occupancy. Matrix-assisted laser desorption ionization-mass spectrometry and metal binding studies suggest that Cu(I) is bound by residues from the first and third domains and no bound copper is detected for the second domain of hCCS in either the full-length or truncated forms of the protein. Copper-induced conformational changes in the essential C-terminal peptide of hCCS are consistent with a "pivot, insert, and release" mechanism that is similar to one proposed for the well characterized metal handling enzyme, mercuric ion reductase.     

Effect of MPTP and l-Deprenyl on Antioxidant Enzymes and Lipid Peroxidation Levels in Mouse Brain

Abstract: Excessive free radical formation or antioxidant enzyme deficiency can result in oxidative stress, a mechanism proposed in the toxicity of MPTP and in the etiology of Parkinson's disease (PD). However, it is unclear if altered antioxidant enzyme activity is sufficient to increase lipid peroxidation in PD. We therefore investigated if MPTP can alter the activity of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX) and the level of lipid peroxidation. l -Deprenyl, prior to MPTP administration, is used to inhibit MPP⁺ formation and its subsequent effect on antioxidant enzymes. MPTP induced a threefold increase in SOD activity in the striatum of C57BL/6 mice. No parallel increase in GSH-PX or CAT activities was observed, while striatal lipid peroxidation decreased. At the level of the substantia nigra (SN), even though increases in CAT activity and reduction in SOD and GSH-PX activities were detected, lipid peroxidation was not altered. Interestingly, l -deprenyl induced similar changes in antioxidant enzymes and lipid peroxidation levels, as did MPTP. Taken together, these results suggest that an alteration in SOD activity, without compensatory increases in CAT or GSH-PX activities, is not sufficient to induce lipid peroxidation.     

Molecular defense systems are expressed in the king bolete (Boletus edulis) growing near metal smelters

The induction of defense systems against metal exposure was investigated in 48 wild-growing fruiting bodies of the king bolete (Boletus edulis) from two areas polluted with several transition metals from smelters, as well as five reference areas. To determine the degree of metal exposure, cadmium (Cd), zinc (Zn), and copper (Cu) were determined in caps of fruiting bodies by atomic absorption spectrophotometry (AAS), whereas mercury (Hg) was determined by cold vapor atomic fluorescence spectrometry (CVAFS). Caps were analyzed further with respect to relative activities of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), as well as concentrations of total glutathione (GSHTOT = GSH + GSSG) and relative concentrations of heat shock protein 70 kDa (HSP70). The results showed that concentrations of the four metals, as well as SOD, CAT and HSP70, were significantly elevated in the exposed group (Mann-Whitney, P < or = 0.001). In contrast, GSHTOT was significantly lowered in the exposed group (P < or = 0.05). Significant positive correlations were established between concentrations of Cd, Zn, Hg, or Cu and activities of SOD (Spearman's P < or = 0.01 for the association between SOD and Cd, P < or = 0.001 for all other metal exposure parameters), CAT (P < or = 0.001 for all exposure parameters), or expression of HSP70 (P < or = 0.001 for all exposure parameters). Significant negative correlations were found between total GSH and Cd (P < or = 0.001), Zn (P < or = 0.001), or Hg (P < or = 0.05). We conclude that antioxidant enzymes are induced in wild-growing B. edulis exposed to environmentally relevant concentrations of potentially toxic transition metals; whereas the net consumption of GSH that occurs with increasing metal exposure may reflect GSH consumption by mechanisms of metal detoxification. Finally, the induction of HSP70 suggests that the antioxidant response and the mechanisms in which GSH is consumed are insufficient for protection against the harmful effects of severe metal stress.     

9-polylysine protein transduction domain: enhanced penetration efficiency of superoxide dismutase into mammalian cells and skin

Antioxidant enzymes, such as superoxide dismutase (SOD) and catalase (CAT), have been considered to have a beneficial effect against various diseases that are mediated by the reactive oxygen species (ROS). Although a variety of modified recombinant antioxidant enzymes have been generated to protect against oxidative stresses, the lack of their transduction ability into cells resulted in a limited ability to detoxify intracellular ROS. To render the SOD enzyme capable of detoxifying intracellular ROS when added extracellularly, cell-permeable recombinant SOD proteins were generated. A human Cu,Zn-superoxide dismutase (Cu,Zn-SOD) gene was fused with a gene fragment that encodes the 9 amino acids Tat protein transduction domain (RKKRRQRRR) of HIV-1 and lysine rich peptide (KKKKKKKKK) in a bacterial expression vector in order to produce a genetic in-frame Tat-SOD and 9Lys-SOD fusion protein, respectively. The expressed and purified Tat-SOD and 9Lys-SOD fusion proteins can transduce into human fibroblast cells, and they were enzymatically active and stable for 24 h. The cell viability of the fibroblast cells that were treated with paraquat, an intracellular superoxide anion generator, was increased by the transduced Tat-SOD or 9Lys-SOD. The transduction efficacy of 9Lys-SOD was more efficient than that of Tat-SOD. We evaluated the ability of the SOD fusion pmteins to transduce into animal skin. This analysis showed that Tat-SOD and 9Lys-SOD fusion proteins efficiently penetrated into the epidermis as well as the dermis of the subcutaneous layer, when sprayed on mice skin (judged by the immunohistochemistry and specific enzyme activities). The enzymatic activity of the transduced 9Lys-SOD was higher than that of Tat-SOD, indicating that the penetration of 9Lys-SOD was more efficient when put into the skin. These results suggest Tat-SOD and 9Lys-SOD fusion proteins can be used as anti-aging cosmetics, or in protein therapy, for various disorders that are related to this antioxidant enzyme and ROS.     

Aluminum effect on the activity of superoxide dismutase and of other antioxygenic enzymes in vitro

The effect of Al on superoxide dismutase (SOD) and on other antioxygenic enzymes: horseradish peroxidase, catalase, and glutathione peroxidase, has been investigated in vitro. In the case of SOD, the effect of metal chelators (EDTA and deferoxamine) and a possible synergistic effect with iron salts have also been tested using the pyrogallol assay. There is no significant inhibitory effect of Al on the activity of any of the above-mentioned enzymes. Noticeable increases in SOD activity were observed when metal chelators were added to the medium, but not when high concentrations of Al were present too, in the case of deferoxamine (DFO). The former fact seems to be a consequence of the chelation of transition metal ions that catalyze pyrogallol autoxidation by a mechanism not inhibitable by SOD, interfering in its action, which may account for part of the DFO antioxidant effect observed in vivo. The latter phenomenon could be owing to a saturation of the chelating capacity of DFO by an excess of Al present in the medium, which should bring the system back to the interfering conditions explained above. It can be concluded that Al, either in the presence or in the absence of iron salts, does not inhibit SOD activity in vitro. Moreover, no significant binding of Al to SOD was demonstrated, and the amounts of its metal constituents, Cu and Zn, were not affected by preincubation of the enzyme with Al. The effect of the different compounds tested on the rate of autoxidation of the indicating scavenger, pyrogallol, and a suitable hypothesis on their role in the oxidation process are also discussed.     

Cd (II) stress response during the growth of Aspergillus niger B 77

Aims:  To investigate the relationship between growth, heavy metal ions uptake and participation of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in the protection of Apergillus niger B 77 against cadmium stress.
Methods and Results:  The stress response of the model fungal strain, under conditions of a wide range of Cd (II) ion concentrations, was investigated by determining the biomass formation, protein biosynthesis, SOD and CAT activities and heavy metal uptake in growing cells. Exposure to heavy metal ions induced an increase in protein content, heavy metal uptake and SOD activity, and a heavy decrease in CAT activity.
Conclusion:  The results obtained indicated that the tolerance of A. niger to Cd (II) was correlated with the heavy metal uptake, reactive oxygen species generation in the cells and the efficiency of antioxidative defence system.
Significance and Impact of the Study:  Evidence is provided for the possibility that oxidative stress plays a major role in the effect of Cd (II) ions on A. niger . These data could offer useful information when creating new strategies and methodological improvements for bioremediation with the participation of fungi.     

矿区废弃地先锋植物齿果酸模在Pb、Zn污染下抗氧化酶系统的变化

作为云南矿区废弃地常见的先锋植物,齿果酸模(Rumex dentatus)已形成对重金属污染的耐性生态型,是理想的逆境生态学研究实验材料.为进一步揭示不同抗氧化酶在先锋植物幼苗早期抗逆境的耐性机理中的作用,采集了来自云南兰坪铅锌矿废弃地的齿果酸模,观察其幼苗多种抗氧化酶在实验室模拟的重金属Pb与Zn单一污染条件下(浓度分别为0,1,5,10,50,100,200 mg/kg)的变化特征.结果表明:随着Pb与Zn单一污染浓度的增加,(1)MDA含量持续上升,与对照相比,在200 mg/kg Pb或Zn单一污染下,MDA分别显著上升了427%和330%;而(2)SOD,POD与CAT三者活性变化特征则各有不同.其中SOD活性呈现先升后降的趋势,POD活性则持续上升;而CAT活性很低,在Zn污染下未检测出,Pb污染下其变化无显著规律.相关性分析结果表明,Pb与Zn单一污染导致先锋植物齿果酸模幼苗产生膜脂过氧化,而抗氧化酶系统在抵御这种不良影响的耐性机制中发挥了一定的作用,且不同酶发挥的效用不同,其中POD发挥了主要作用.     

Association between dietary fat and antioxidant status of Tunisian type 2 diabetic patients

BACKGROUND: The antioxidant enzymes: superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase (GSH-Px) provide a defense against the damage of cells by reactive oxygen species, which increased in diabetic state. It was demonstrated that dietary treatment could improve the antioxidant status in patients with type 2 diabetes mellitus. This study was undertaken to determine if erythrocyte Cu/Zn SOD and GSH-Px activities correlate with dietary nutrients in 35 selected type 2 diabetic patients (21 women and 14 men) without diabetic complications. RESULTS: We found that erythrocyte Cu/Zn SOD was diminished in patients with poor controlled diabetes and GSH-Px activity was significantly decreased in obese compared with non-obese type 2 diabetic patients (1.07+/-0.87 and 2.36+/-1.99 U/ml, respectively; P=0.024). Both erythrocyte Cu/Zn SOD and GSH-Px activities were positively correlated to erythrocyte omega3-polyunsaturated fatty acids (PUFA). In non-obese diabetic patients, only GSH-Px activity was correlated negatively to the fraction of linoleic acid (18:2omega6) and arachidonic acid (20:4omega6) in erythrocytes phospholipids. CONCLUSIONS: The data of this study reveal that activities of erythrocyte antioxidant enzymes were altered in type 2 diabetic patients. Further studies are needed to determine if diet supplemented with omega3-PUFA is required to improve antioxidant defense system in diabetic state.