Antioxidant status in anorexia nervosa

Bone mineral density and oxidative stress in adolescent girls with anorexia nervosa

Oxidative stress appears to be involved in the pathogenesis of osteoporosis-a serious complication of anorexia nervosa (AN). We evaluated the oxidative status in adolescent girls with AN and its potential relationship with bone mineral density (BMD). Girls with AN (n = 43) and age-matched healthy controls (n = 20) underwent anthropometric and BMD examination. Markers of bone turnover, oxidative stress, and antioxidant status were measured. Participants with AN and controls did not differ in BMD at the lumbar spine (p = 0.17) and total body less head BMD (p = 0.08). BMD at the total hip was lower (p < 0.001) in the AN group compared with the controls. Levels of antioxidant status markers-ferric reduction antioxidant power, total antioxidant capacity, and reduced and oxidized glutathione ratio (all p < 0.001)-were significantly lower, whereas those of advanced oxidation protein products (AOPP), fructosamines, and advanced glycation end products (AGEs) (all p < 0.001) were higher in AN patients than in healthy controls. BMD and bone turnover markers were positively correlated with antioxidant status markers, while they were negatively correlated with AOPP, fructosamines, and AGEs levels.  Conclusion: This is the first study to assess a potential association between oxidative status and BMD in adolescents with AN. We demonstrated that in young girls, the imbalance of oxidative status and reduced BMD are concurrently manifested at the time of the diagnosis of AN. Disturbance of oxidative status could play a pathogenetic role in AN-associated decreased BMD. What is Known: • Osteoporosis is a serious complication of AN, and in affected adolescents may result in a permanent deficit in bone mass. • Oxidative and carbonyl stress may be involved in the development of bone loss. What is New: • Adolescents girls with AN have impaired antioxidant defense and increased oxidative damage to biomolecules. • Disturbance of oxidative status could affect bone loss and could contribute to decreased BMD in adolescent females with AN.

Anorexia nervosa and pancreatitis

Acute pancreatitis is a condition whereby erroneous activation of trypsin and zymogen results in pancreatic autodigestion. There are many aetiologies, with alcohol intake and gallstones being the most common. Anorexia nervosa is an eating disorder in which patients' reduced food intake and psychological aversion of weight gain can result in low body weight and malnourishment. The link between pancreatitis and anorexia nervosa is not well understood; this article explores the theorised pathophysiology connecting the two conditions, as well as the optimal management of patients when the conditions co-exist based on current literature. A literature search was performed using MEDLINE, EMBASE and CINAHL databases for all journal articles on the topic of presentations of acute or chronic pancreatitis in adults with anorexia nervosa. The literature proposes various links between anorexia nervosa and pancreatitis. It is theorised that pancreatitis may arise as a result of malnourishment itself or secondary to the refeeding process. Some explanations focus on the histopathological changes to the pancreas that malnourishment induces, while others focus on the enzymatic changes and oxidative damage that arise in the malnourished state. More mechanical mechanisms such as gastric dilatation, gastrointestinal ileus and compartmental fluid shift during refeeding have also been proposed as explanations for the link between the conditions. Some medications used in the management of anorexia nervosa have also been linked to pancreatitis.

Oxidative status in plasma, urine and saliva of girls with anorexia nervosa and healthy controls: a cross-sectional study

BACKGROUND

Anorexia nervosa (AN) is a serious psychosomatic disorder with unclear pathomechanisms. Metabolic dysregulation is associated with disruption of redox homeostasis that might play a pivotal role in the development of AN. The aim of our study was to assess oxidative status and carbonyl stress in plasma, urine and saliva of patients with AN and healthy controls.

METHODS

Plasma, spot urine, and saliva were collected from 111 girls with AN (aged from 10 to 18 years) and from 29 age-matched controls. Markers of oxidative stress and antioxidant status were measured using spectrophotometric and fluorometric methods.

RESULTS

Plasma advanced oxidation protein products (AOPP) and advanced glycation end products (AGEs) were significantly higher in patients with AN than in healthy controls (by 96, and 82%, respectively). Accordingly, urinary concentrations of AOPP and fructosamines and salivary concentrations of AGEs were higher in girls with AN compared with controls (by 250, and 41% in urine; by 92% in saliva, respectively). Concentrations of thiobarbituric acid reactive substances (TBARS) in saliva were 3-times higher in the patients with AN than in the controls. Overall antioxidants were lower in plasma of girls with AN compared to the controls, as shown by total antioxidant capacity and ratio of reduced and oxidized glutathione (by 43, and 31%, respectively).

CONCLUSIONS

This is the first study assessing wide range of markers of oxidative status in plasma, urine and saliva of the patients with AN. We showed that both, higher levels of markers of oxidative stress and lower antioxidants play a role in redox disruption. Restoration of redox homeostasis might be of the clinical relevance.

Nutrition Can Help DNA Repair in the Case of Aging

Micronutrients such as vitamins and trace elements are crucial for maintaining the health of all organisms. Micronutrients are involved in every cellular/biochemical process. They play roles in proper heart and brain functioning, influence immunological responses, and antioxidant defense systems. Therefore, prolonged deficiency in one or more micronutrients leads to cardiovascular or neurodegenerative disorders. Keeping micronutrients at adequate levels is especially important for seniors. They are prone to deficiencies due to age-associated functional decline and often to a diet poor in nutrients. Moreover, lack of micronutrients has an indirect impact on the genome. Their low levels reduce the activity of antioxidant enzymes, and therefore inhibit the efficiency of defense against free radicals which can lead to the formation of DNA lesions. The more DNA damage in the genetic material, the faster aging at the cellular level and a higher risk of pathological processes (e.g., carcinogenesis). Supplementation of crucial antioxidative micronutrients such as selenium, zinc, vitamin C, and vitamin E seems to have the potential to positively influence the condition of an aging organism, including minimizing inflammation, enhancing antioxidative defense, and limiting the formation of DNA lesions. In consequence, it may lead to lowering the risk and incidence of age-related diseases such as cardiovascular diseases, neurodegenerative diseases, and malnutrition. In this article, we attempt to present the synergistic action of selected antioxidant micronutrients (vitamin C, vitamin E, selenium, and zinc) for inhibiting oxidative stress and DNA damage, which may impede the process of healthy aging.

Anorexia Nervosa and the Immune System-A Narrative Review

The pathogenesis of an increasing number of chronic diseases is being attributed to effects of the immune system. However, its role in the development and maintenance of anorexia nervosa is seemingly under-appreciated. Yet, in examining the available research on the immune system and genetic studies in anorexia nervosa, one becomes increasingly suspicious of the immune system’s potential role in the pathophysiology of anorexia nervosa. Specifically, research is suggestive of increased levels of various pro-inflammatory cytokines as well as the spontaneous production of tumor necrosis factor in anorexia nervosa; genetic studies further support a dysregulated immune system in this disorder. Potential contributors to this dysregulated immune system are discussed including increased oxidative stress, chronic physiological/psychological stress, changes in the intestinal microbiota, and an abnormal bone marrow microenvironment, all of which are present in anorexia nervosa.

Study of salivary and serum vaspin and total antioxidants in anorexia nervosa

OBJECTIVES

Patients with anorexia nervosa (AN) are primarily at high risk of multiple somatic complications, including oral diseases. In recent years, a number of new molecules that may play a potentially important role in AN progress and prognosis have been identified in saliva, but their exact roles are still poorly understood. Two such group of substances are antioxidants and vaspin. The purpose of this observational, cross-sectional study was to measure both the salivary and serum total antioxidant status (TAS), and vaspin (VASP) concentrations of patients with AN in comparison to an average population.

MATERIAL AND METHODS

Ninety subjects participated (30 patients with AN, 60 matched healthy control subjects). A clinical examination was made, and blood and salivary samples were taken during the acute stage of AN (BMI < 15 kg/m²) in the first week of hospitalization. Enzyme immunoassay (ELISA) suitable for measuring VASP and colorimetric assay for TAS were used.

RESULTS

Anorexic patients had significant reductions in salivary flow, TAS, and an elevation in VASP levels in their saliva and serum. Significant correlations between TAS, VASP, salivary flow, and nutritional status were detected.

CONCLUSION

Determination of TAS and VASP in combined biological material confirmed that saliva might be a reliable non-invasive source of information for potent nutritional biomarkers.

CLINICAL RELEVANCE

Our findings suggest that VASP cannot be excluded, as its increased concentration in saliva is an adaptive mechanism in reduced TAS, one resulting from diminished salivary secretion. It is therefore worth conducting further research aimed at recognizing the role of TAS and VASP in the saliva of underweight patients.

Micronutrient Status in 153 Patients with Anorexia Nervosa

Micronutrient status in Anorexia Nervosa (AN) has been poorly documented and previous data are often contradictory. We aimed to assess micronutrient status in a large population of AN patients. The relationships between micronutrient status and body composition were also determined. Anthropometric, biochemical parameters and body composition data were collected at referral in 153 patients with AN (28.5 ± 11 years). At least one trace element deficit was observed in almost half of patients; the most frequent was selenium deficit (40% of patients). At least one vitamin deficit was observed in 45.7% of patients, mostly vitamin A and B9. Albumin, transthyretin and CRP were within normal range in most patients. No correlations were found between body composition and micronutrient status. Our study suggests that micronutrient status is often altered in AN patients, which may contribute to neuropsychiatric dysfunction. Monitoring of micronutrients and correction of deficits should be included in the routine care of AN patients.

Oxidative Stress and Antioxidant Levels in Patients with Anorexia Nervosa after Oral Re-alimentation: A Systematic Review and Exploratory Meta-analysis

Oxidative stress markers seem to be higher in patients with anorexia nervosa (AN) than healthy controls, but the potentially beneficial effects of weight gain is not known. We calculated random effects standardised mean differences (SMDs) as effect size measures of oxidative stress marker changes after re-alimentation reported in two or more studies, summarising others descriptively. Seven longitudinal studies (n = 104) were included. After a median follow-up period of 8 weeks, AN patients significantly increased their body mass index (15.1 ± 2.1 to 17.1 ± 2.2, p < 0.0001). This weight gain was followed by a significant increase in serum levels of the antioxidant albumin (studies = 6, SMD = 0.50, 95%CI = 0.18; 0.82, p = 0.002; I(2) = 16%) and a significant decrease in the oxidative stress marker Apolipoprotein B (studies = 2, n = 19, SMD = -0.85, 95%CI = -1.53; -0.17, p = 0.01; I(2) = 0). In one study, catalase and total antioxidant capacity increased, whilst superoxide dismutase significantly decreased. In conclusion, oral re-alimentation, even without full-weight normalisation, seems to improve oxidative stress in people with AN.

Oxidative stress and antioxidant levels in patients with anorexia nervosa: A systematic review and exploratory meta-analysis

OBJECTIVE

To systematically review and meta-analyze oxidative stress and antioxidant markers in anorexia nervosa (AN).

METHODS

Electronic PubMed search from database inception until 12/31/2013. Out of 1062 hits, 29 studies comparing oxidative stress/antioxidant markers between patients with AN and healthy controls (HCs) with a total of 1,729 participants (AN = 895, HCs = 834) were eligible. Data about oxidative stress and antioxidant markers, independent of their source, were extracted. We calculated random effects standardized mean differences (SMDs) as effect size measures for outcomes reported in ≥5 studies; others were summarized descriptively.

RESULTS

Compared to HCs, AN patients showed significantly higher apolipoprotein B (ApoB) levels (studies = 7; n = 551; SMD = 0.75; p = .0003, I(2)  = 74%), with higher age being associated with higher ApoB (Coefficient: 0.61 ± 0.15, p < .0001), whereas BMI (p = .15) and measurement method (p = .70) did not moderate the results. Serum albumin levels were similar between AN and HCs (studies = 13; n = 509; SMD =-0.19; 95%CI: -0.62 to 0.24; p = .38; I(2)  = 81%), with neither age (p = .84) nor BMI (p = .52) being significant moderators. Lower superoxide dismutase levels were reported in 2 studies, while findings for vitamin A and its metabolites were inconclusive. In single studies, patients with AN had significantly higher catalase and nitric oxide (NO) parameter levels (platelet NO, exhaled NO and nitrites), such as lower glutathione and free cysteine levels, compared to HCs.

DISCUSSION

AN appears to be associated with some markers of increased oxidative stress. Additional research is needed to discern whether oxidative stress is a potential cause or effect of AN, and whether treatments improving oxidative stress could be useful in AN.

Antioxidant activity and nutritional status in anorexia nervosa: effects of weight recovery

Few studies are focused on the antioxidant status and its changes in anorexia nervosa (AN). Based on the hypothesis that renutrition improves that status, the aim was to determine the plasma antioxidant status and the antioxidant enzymes activity at the beginning of a personalized nutritional program (T₀) and after recovering normal body mass index (BMI) (T₁). The relationship between changes in BMI and biochemical parameters was determined. Nutritional intake, body composition, anthropometric, hematological and biochemical parameters were studied in 25 women with AN (19.20 ± 6.07 years). Plasma antioxidant capacity and antioxidant enzymes activity were measured. Mean time to recover normal weight was 4.1 ± 2.44 months. Energy, macronutrients and micronutrients intake improved. Catalase activity was significantly modified after dietary intake improvement and weight recovery (T₀ = 25.04 ± 1.97 vs. T₁ = 35.54 ± 2.60μmol/min/mL; p < 0.01). Total antioxidant capacity increased significantly after gaining weight (T₀ = 1033.03 ± 34.38 vs. T₁ = 1504.61 ± 99.73 μmol/L; p < 0.01). Superoxide dismutase activity decreased (p < 0.05) and glutathione peroxidase did not change. Our results support an association between nutrition improvement and weight gain in patients with AN, followed by an enhancement of antioxidant capacity and catalase antioxidant system.

Oxidative stress and abnormal lipid profile are common factors in students with eating distress

Numerous studies on complications associated with eating disorders have been conducted worldwide. However such studies are limited in the Indian scenario. Hence, we attempted to analyse the presence of oxidative stress along with total lipid profiling of students with eating distress in Mysore, South India. A biochemical test panel was conducted using serum samples of controls and subjects. Results were statistically analyzed using SPSS software version 14. Analysis of variance was used to identify significant differences between study groups. Variations in all parameters confirmed the occurrence of oxidative stress and abnormal lipid contents in students prone to eating disorders.

Altered mitochondrial function and oxidative stress in leukocytes of anorexia nervosa patients

Context

Anorexia nervosa is a common illness among adolescents and is characterised by oxidative stress.

Objective

The effects of anorexia on mitochondrial function and redox state in leukocytes from anorexic subjects were evaluated.

Design and setting

A multi-centre, cross-sectional case-control study was performed.

Patients

Our study population consisted of 20 anorexic patients and 20 age-matched controls, all of which were Caucasian women.

Main outcome measures

Anthropometric and metabolic parameters were evaluated in the study population. To assess whether anorexia nervosa affects mitochondrial function and redox state in leukocytes of anorexic patients, we measured mitochondrial oxygen consumption, membrane potential, reactive oxygen species production, glutathione levels, mitochondrial mass, and complex I and III activity in polymorphonuclear cells.

Results

Mitochondrial function was impaired in the leukocytes of the anorexic patients. This was evident in a decrease in mitochondrial O₂ consumption (P<0.05), mitochondrial membrane potential (P<0.01) and GSH levels (P<0.05), and an increase in ROS production (P<0.05) with respect to control subjects. Furthermore, a reduction of mitochondrial mass was detected in leukocytes of the anorexic patients (P<0.05), while the activity of mitochondrial complex I (P<0.001), but not that of complex III, was found to be inhibited in the same population.

Conclusions

Oxidative stress is produced in the leukocytes of anorexic patients and is closely related to mitochondrial dysfunction. Our results lead us to propose that the oxidative stress that occurs in anorexia takes place at mitochondrial complex I. Future research concerning mitochondrial dysfunction and oxidative stress should aim to determine the physiological mechanism involved in this effect and the physiological impact of anorexia.

Tumour necrosis factor alpha and oxidative stress as maintaining factors in the evolution of anorexia nervosa

OBJECTIVE

Aim of the study was to evaluate tumour necrosis factor α (TNF-α) axis and oxidative status in patients with anorexia nervosa (AN) seeking a possible correlation with both nutritional status and evolution of the disease.

SUBJECTS AND METHODS

Thirty-nine consecutive women with AN and an age-matched healthy control group were studied. Patients were 26±9 yr, with a body mass index (BMI) of 13.9±2 kg/m(2). TNF-α, its receptors TNF-R55 and TNF-R75, and oxidative status markers (selenium, ascorbic/ dehydroascorbic acid, retinol, α-tocopherol, selenium-dependent gluthatione peroxidase, reduced/oxidated gluthatione) were measured. A correlation with both nutritional indexes (body weight, BMI, albumin, prealbumin, transferrin, lymphocyte count) and disease duration was investigated. Pearson's correlation and unpaired Student's t-test were used to compare patients and controls.

RESULTS

TNF-α and oxidative status markers were significantly higher in patients than controls and TNF-α was directly related to dehydroascorbic acid (p<0.05). Both TNF-R55 and TNF-R75 were higher in patients with duration of disease longer than one year as compared to controls and patients with shorter duration. Receptors inversely correlated with BMI (p<0.05 and p<0.01) and directly with disease duration (p<0.05). Inverse correlation between disease duration and BMI was present (p<0.01).

CONCLUSIONS

The study showed activation of TNF-α axis and oxidative stress in AN patients, as well as correlation between the two systems. Due to the correlation between TNF receptors and both BMI and disease duration, a possible role of pro-inflammatory cytokines in the evolution of the eating disorder is suggested.

Coenzyme Q10 concentration in plasma and blood cells of juvenile patients hospitalized for anorexia nervosa

The antioxidant status of coenzyme Q10 (CoQ10) was investigated in plasma, erythrocytes, and platelets of juvenile patients with anorexia nervosa. Blood for analysis of the CoQ10 status was taken from 16 juvenile patients suffering from anorexia nervosa (restricting form) at the time point of admission to the hospital and at discharge after about 12 weeks. Plasma and blood cells isolated by a density gradient were stored at -84 °C until analysis. CoQ10 concentration and redox status were measured by high pressure liquid chromatography with electrochemical detection and internal standardization. The improvement of physical health during the hospital refeeding process was followed up by the body mass index (BMI). The antioxidant status of plasma CoQ10 in juvenile patients suffering from anorexia nervosa indicated no abnormalities in comparison to healthy controls. However, the decreased concentration of CoQ10 observed in platelets at the time point of hospital admission may represent mitochondrial CoQ10 depletion. This initial deficit improved during the hospital refeeding process. The platelet CoQ10 concentration showed a positive correlation to the BMI of the patients.

Anorexia nervosa: a role for L-arginine supplementation in cardiovascular risk factors?

OBJECTIVE

The aim of the present study was to evaluate the effects of a short-term oral L-arginine treatment on platelet NO production, intracellular calcium concentration, iNOS and eNOS expression, in AN patients.

METHOD

Forty outpatients belonging to restricting subtype and 40 normal participants age and sex matched were enrolled in the study.

RESULTS

NO production was significantly elevated in the platelets from AN patients compared with controls while [Ca(2+)](i) was significantly decreased in patients with respect to controls. Western blot analysis demonstrated that iNOS isoform was more pronounced in the cell lysates from AN patients than controls. After supplementation with L-arginine, both NO production and [Ca(2+)](i) seem to return to control levels, suggesting a probable recovery of their metabolisms. The same was found after western blot analysis of NOS expression.

DISCUSSION

The results here proposed can be considered highly indicative of a positive effect of L-arginine supplementation on platelet NO production in AN patients.

Oxidative stress, l-arginine-nitric oxide and arginase pathways in platelets from adolescents with anorexia nervosa

Anorexia nervosa (AN) is associated with high cardiovascular mortality. Nitric oxide (NO) inhibits platelet function and regulates the cardiovascular homeostasis. The aim of this study was to investigate the l-arginine-NO-GMPc and arginase pathways and oxidative stress in platelets from patients with AN. Intraplatelet l-arginine transport, NOS expression and activity, cGMP levels, platelet aggregation, arginase expression and oxidative stress were measured in adolescent patients with AN (n=11) and healthy controls (n=12). Plasma l-arginine levels were significantly reduced in AN. l-arginine transport, NOS activity and cGMP basal levels were reduced in platelets associated with unchanged platelet aggregability. The expression of NOS isoforms was not affected. TBARS production was diminished, while the activity of superoxide dismutase was elevated in AN patients. There was an overexpression of arginase II in AN. Alterations of l-arginine-NO-GMPc and arginase pathways in platelets can be early predictors of the incidence of cardiovascular disease into adult life in AN.

Lipoproteins obtained from anorexia nervosa patients induce higher oxidative stress in U373MG astrocytes through nitric oxide production

Eating disorders (ED) are a group of important psychiatric disorders that affect young men and women, and can have serious consequences. Among all ED, anorexia nervosa (AN) is the most typical but also the most severe. The pathogenesis of AN is multifactorial and a great variety of cognitive deficits may contribute to its pathogenesis. The present study is aimed to measure NO and peroxynitrite production, iNOS and nNOS expression by Western immunoblot after incubation of AN lipoproteins at different times with human astrocytoma cells. The AN-HDL treated cells showed an increased production of NO at 3 h versus control-HDL treated cells and a decreased production at 24 h. Regarding LDL, a significant increase of NO production was obtained both at 3 and 24 h. The AN-HDL and AN-LDL treated cells showed an increased production of peroxynitrite both at 3 and 24 h compared to control lipoproteins. Densitometric analysis of bands indicated that both iNOS and nNOS protein levels were significantly higher in the cells incubated with AN lipoproteins compared to cells incubated with control lipoproteins both at 3 and 24 h. Although the pathogenesis of AN remains uncertain, evidence exists that modifications to the lipoprotein profile and cholesterol, structural alterations of phospholipids and integral constituents of myelin and synaptosomes may be related to psychotic disorders and body image distortion common to AN. Thus, a relevant pathophysiological association between NO and depression is certainly a possibility, as well as a central role played by NO in the pathogenesis.

A case report of oxidative stress in a patient with anorexia nervosa

OBJECTIVE

Liver injury is well known as a complication of anorexia nervosa (AN), and steatosis of the liver has been thought to be the main cause of the injury. However, the precise mechanism for the liver injury is still unclear.

METHOD AND RESULTS

We had a chance to examine the histological change of the liver with AN, and found that not only fat deposit but also peroxidated lipid products and irons were recognized in hepatocytes.

CONCLUSION

Our present case demonstrates that oxidative stresses in hepatocytes, which might be associated with iron deposition, could be involved in the pathogenesis of liver injury in patients with AN.

Decreased glutathione in patients with anorexia nervosa. Risk factor for toxic liver injury?

OBJECTIVE

To investigate glutathione and amino acids related to glutathione metabolism in patients with anorexia nervosa in order to test the hypothesis that these patients exhibit a deficiency of glutathione and therefore might be at an increased risk of developing toxic liver injury.

DESIGN

Controlled observatory study and case report.

SETTING

University Hospital.

SUBJECTS

Subjects included 11 female patients with anorexia nervosa and 12 healthy female controls.

INTERVENTIONS

Determination of fasting free and total glutathione, homocysteine, vitamins B(6) and B(12) and folic acid in plasma.

RESULTS

A 14-y-old patient with a body mass index of 12.6 kg/m(2) presented with markedly elevated transaminases (ALAT >50 x upper limit of normal), and paracetamol was detected in her blood. Patients with anorexia nervosa exhibited lower circulating concentrations of free cysteine (8.9+/-1.5 vs 12.0+/-1.4 micromol/l) and free and total glutathione (5.0+/-1.3 vs 7.1+/-1.2 and 11.2+/-3.8 vs 16.2+/-5.0 micromol/l, respectively). The plasma concentrations of homocysteine (17.5+/-4.9 vs 12.0+/-3.8 micromol/l) and also of glycine (194+/-37 vs 143+/-41 micromol/l) and glutamine (422+/-51 vs 353+/-51 micromol/l) were significantly higher in patients with anorexia nervosa who were not deficient in folic acid, vitamin B(6) and B(12).

CONCLUSIONS

Lower plasma concentrations of glutathione suggest lower intracellular concentrations of the tripeptide. Higher homocysteine, glycine and glutamine concentrations point to a decreased utilization of these amino acids for glutathione synthesis and an impairment of trans-sulfuration. Consequently, the capacity of patients with anorexia nervosa to detoxify electrophilic metabolites and reactive oxygen species via glutathione may be impaired.

Oxidative stress in Rett syndrome

The investigation of parameters that might influence the neurological evolution of Rett syndrome might also yield new information about its pathogenic mechanisms. Oxidative stress caused by oxygen free radicals is involved in the neuropathology of several neurodegenerative disorders, as well as in stroke and seizures. To evaluate the free radical metabolism in Rett syndrome, we measured red blood cell antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase) and plasma malondialdehyde, as lipid peroxidation marker in a group of patients with Rett syndrome. No significant differences were observed in erythrocyte glutathione peroxidase, glutathione reductase and catalase activities, between the Rett syndrome patients and the control group. Erythrocyte superoxide dismutase activities were significantly decreased in Rett syndrome patients (P<0.001) compared with the control group. Plasma malondialdehyde concentrations were significantly increased in Rett syndrome patients (P<0.001). An unbalanced nutritional status in Rett syndrome might explain the reduced enzyme activity found in these patients. Our results suggest that free radicals generated from oxidation reactions might contribute to the pathogenesis of Rett syndrome. The high levels of malondialdehyde reflect peroxidative damage of biomembranes that may contribute to progressive dementia, impaired motor function, behavioural changes, and seizures, in Rett syndrome. We found a probable relationship between the degree of oxidative stress and the severity of symptoms, which should be further investigated with a larger number of patients in different disease stages.