Kaluce Gonçalves de Sousa Almondes

O papel das selenoproteínas no câncer

Evidence has shown that metabolic disorders are common in tumor cells, leading to increased oxidative stress. The increase in the production of reactive oxygen species (ROS) associated with low antioxidant activity has been related to several types of cancer. Selenium, an antioxidant micronutrient, may function as an antimutagenic agent, preventing the malignant transformation of normal cells. A review of the literature was conducted based on a survey of articles published between 2000 and 2009 in the PubMed database; 39 articles that analyzed the relationship between cancer, oxidative stress and selenium supplementation were selected. The protective effect of this mineral is especially associated with its presence in the glutathione peroxidase and thioredoxin reductase, enzymes that are known to protect DNA and other cellular components against oxidative damage caused by ROS. Several studies have shown reduced expression of these enzymes in various types of cancer, especially when associated with low intake of selenium, which may increase the damage. Selenium supplementation appears to reduce the risk of some types of cancer by reducing oxidative stress and DNA damage. However, further studies are needed to clarify the adequate dose of selenium for each situation (sex, geographic location, and type of cancer).

Enzyme activity of superoxide dismutase and zincemia in women with preeclampsia

INTRODUCTION Preeclampsia is a complex syndrome of unknown aetiologic origin. It is characterized by the clinical triad of hypertension, edema and protenuria. Current concepts of the genesis of preeclampsia include endothelial dysfunction and oxidative stress. OBJECTIVE This study assessed the relationship between the activity of superoxide dismutase, the zincemia and the preeclampsia. METHODS A case-control study was carried out with 94 women, age between 17 and 44 years, which were divided in two groups: women with preeclampsia (n = 44) and control group women with normal pregnancy (n = 50). The activity of superoxide dismutase enzyme was determined according to Ransod kit. Zinc concentrations in plasma and erythrocytes were determined using the flame atomic absorption spectrophotometry technique, both determined before delivery and during puerperium. Students t-test and the paired t-test were used for statistical analysis, and significance was established at p < 0.05. RESULTS The study revealed plasma hypozincemia more pronounced in women with severe preeclampsia (p < 0.05). This behavior was not observed in erythrocytes, whose concentrations remained stable, before delivery and puerperium in women with preeclampsia and normal pregnancy. The antioxidant activity of the enzyme superoxide dismutase was found elevated in women with and without preeclampsia (p>0.05), with significant reduction in activity in the postpartum period (p < 0.05) in both groups studied (p>0.05). CONCLUSIONS This study shows there are alterations in biochemical parameters of zinc in women with preeclampsia. The activity of superoxide dismutase shows that this marker cannot be used to predict the evolution of the disease.

Selenium inadequacy is not associated with oxidative stress in child and adolescent acute lymphocytic leukemia survivors

OBJECTIVE Acute lymphocytic leukemia (ALL) and its subsequent treatment may provoke increased oxidative stress. The aim of this study was to investigate the antioxidant status of children and adolescents who had received ALL therapy, and to test the hypothesis that selenium (Se) inadequacy is correlated with reduced defenses against oxidative stress in this population. METHODS This case-control study involved 24 patients between ages 5 and 13 y who had been treated successfully for ALL (ALL group) and 60 children of similar age and socioeconomic background with no clinical history of leukemia (control group). Dietary intake of Se was evaluated by the 24-h recall method, and the concentrations of Se in plasma, erythrocytes, and urine determined. Antioxidant status was assessed by analysis of the oxidative stress markers, namely, superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), α-tocopherol, and 8-oxo-deoxyguanosine (8-oxo-dG). RESULTS There were no between-group differences with respect to plasma (P = 0.122), erythrocyte (P = 0.202), urinary (P = 0.608), or dietary (P = 0.757) levels of Se. GPx activity was significantly (P < 0.001) reduced in the ALL group compared with the control group, whereas SOD activity and MDA concentrations were similar. The concentrations of α-tocopherol and 8-oxo-dG were significantly increased in the ALL group compared with the control group (P < 0.001 and P = 0.031, respectively). CONCLUSION All participants were Se inadequate, but such inadequacy was not correlated with reduced defenses against oxidative stress. However, individuals of the ALL group were with increased oxidative stress compared with the control group, possibly due to previous disease and to intensive polychemotherapy.

Association of reduced zinc status with poor glycemic control in individuals with type 2 diabetes mellitus

This study evaluated the relationship between the zinc-related nutritional status and glycemic and insulinemic markers in individuals with type 2 diabetes mellitus (T2DM). A total of 82 individuals with T2DM aged between 29 and 59 years were evaluated. The concentration of zinc in the plasma, erythrocytes, and urine was determined by the flame atomic absorption spectrometry method. Dietary intake was assessed using a 3-day 24-h recall. In addition, concentrations of serum glucose, glycated hemoglobin percentage, total cholesterol and fractions, triglycerides, and serum insulin were determined. The insulin resistance index (HOMA-IR) and β-cell function (HOMA- β) were calculated. The markers of zinc status (plasma: 83.3±11.9μg/dL, erythrocytes: 30.1±4.6μg/g Hb, urine: 899.1±622.4μg Zn/24h, and dietary: 9.9±0.8mg/day) were classified in tertiles and compared to insulinemic and glycemic markers. The results showed that lower zinc concentrations in plasma and erythrocytes, as well as its high urinary excretion, were associated with higher percentages of glycated hemoglobin, reflecting a worse glycemic control in individuals with T2DM (p<0.05). Furthermore, there was a significant inverse correlation between plasma zinc levels and glycated hemoglobin percentage (r=-0.325, p=0.003), and a positive correlation between urinary zinc excretion and glycemia (r=0.269, p=0.016), glycated hemoglobin percentage (r=0.318, p=0.004) and HOMA-IR (r=0.289, p=0.009). According to our study results, conclude that T2DM individuals with reduced zinc status exhibited poor glycemic control.

GPX1 Pro198Leu polymorphism and GSTM1 deletion do not affect selenium and mercury status in mildly exposed Amazonian women in an urban population

Mercury is potent toxicant element, but its toxicity can be reduced by forming a complex with selenium for safe excretion. Considering the impact of mercury exposure in the Amazon region and the possible interaction between these two elements, we aimed to assess the effects of Pro198Leu polymorphism to GPX1 and GSTM1 deletion, on mercury levels in a population from Porto Velho, an urban locality in the Brazilian Amazon region. Two hundred women from the capital city of Rondônia state were recruited for this study with 149 deemed suitable to participate. We assessed dietary intake using 24-hour recall. Selenium levels in plasma and erythrocytes were measured using hydride generation quartz tube atomic absorption spectroscopy and total hair mercury using cold vapor atomic absorption spectrometry. Oxidative stress parameters (GPx activity, oxygen radical absorbency capacity [ORAC] and malondialdehyde [MDA]) were also analyzed. All participants were genotyped for Pro198Leu polymorphism and GSTM1 deletion. We observed that this population presented high prevalence of selenium deficiency, and also low levels of mercury, likely due to food habits that did not include selenium-rich food sources or significant consumption of fish (mercury biomagnifiers) regularly. Univariate statistical analysis showed that Pro198Leu and GSTM1 genotypes did not affect selenium and mercury levels in this population. Pro198Leu polymorphism and GSTM1 deletion had no effect on mercury levels in mildly exposed people, suggesting these genetic variants impact mercury levels only in highly exposed populations.

Mineral status and superoxide dismutase enzyme activity in Alzheimer’s disease

The study evaluated the dietary intake of zinc and copper, as measured by plasma and erythrocyte concentrations, the Cu/Zn ratio and measure the erythrocyte superoxide dismutase enzyme (eSOD) activity and the relationship between these markers and the degree of dementia in elderly individuals with and without Alzheimers Disease (AD). A total of 93 elderly people aged 60-94 years were divided into two groups: with AD (n=44) and without AD (n=49). The NINCDS-ADRDA criteria were used for diagnosing AD, and dementia staging was determined using the Clinical Dementia Rating (CDR) scale. The dietary intake of Zn and Cu was obtained from a standard 3-day food record. Plasma and erythrocyte concentrations of the minerals were determined by flame atomic absorption spectrophotometry and by measuring eSOD activity in an automatic biochemical analyzer. The results showed dietary intake of Zn and Cu above the reference values with no differences observed between the two groups (p>0.05). Plasma and erythrocyte normocupremia as well as alteration in the Zn pool, with its reduced plasma concentrations and high in the erythrocytes, were observed in both groups (p>0.05). The plasma Cu/Zn ratio were not significantly different in patients with and without AD (p>0.05). The eSOD activity was high in both patient groups (p>0.05). However, among elderly patients with AD there was a positive correlation between this marker and dementia severity. According to our study results, we conclude that plasma and erythrocyte concentrations of Cu and Zn, as well as Cu/Zn ratio among elderly individuals is not related to Alzheimers Disease. However, antioxidant activity of eSOD is associated with dementia severity.

Influence of liver transplantation in the nutritional profile of severe cirrhotic patients

OBJECTIVE The aim of this study was to analyze the influence of liver transplantation in food intake and nutritional status of severe cirrhotic patients. METHODS The sample consisted of 23 patients who underwent liver transplantation. Three 24-hour dietary recall were applied and anthropometric measurements were collected before and three months after transplantation. The consumption of macronutrients and fat soluble vitamins were also evaluated. The anthropometric data evaluated were body mass index, abdominal circumference, percentage of adequacy of arm circumference, triceps skinfold thickness and arm muscle circumference. Related mean comparison tests, comparison of changes in the proportions of categorical variables and correlation of quantitative variables were used in the statistical analysis. Data were considered to be significant when p < 0.05. RESULTS Most patients were female and aged between 40 and 65 years. The average consumption of calories, proteins, lipids, cholesterol and monounsaturated fatty acids was significantly higher after liver transplantation (p < 0.05). The average of anthropometric parameters did not differ significantly between the evaluated times. There was no significant change in nutrient intake or anthropometric classification after transplantation. Most patients were classified as malnourished or overweight after transplantation, according to some anthropometric parameters. CONCLUSION Food consumption changed after transplantation. There was no change in the nutritional status from pre- to post-transplant but, in general, most patients had altered nutritional status in both evaluation moments.

Consumption of nutrients with antioxidant action and its relationship with lipid profile and oxidative stress in student users of a university restaurant

INTRODUCTION The relationship between diet and health has aroused scientific interest, especially the consumption of antioxidant nutrients naturally present in foods, because of its action against the deleterious effects of free radicals in the body. OBJECTIVE This study aimed to estimate the intake of antioxidant nutrients and its relationship with lipid profile and oxidative stress in student users of a university restaurant in comparison with non-users. METHODS This cross-sectional study involved 145 university students divided into two groups: users of the university restaurant (group 1, n = 73) and non-users (group 2, n = 72). We measured body mass index and waist circumference, and estimated the intake of antioxidant micronutrients. Serum concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglyceride levels, and plasma concentrations of malondialdehyde were determined. RESULTS AND CONCLUSIONS Intake of copper, zinc, selenium, and vitamin C were within the recommendations in both groups, and vitamins A and E were below the reference values. There was a correlation between the intake of vitamin C and triglycerides. Group 1 members had better dietary patterns in relation to antioxidant micronutrients, reflecting less atherogenic lipid profile and lower exposure to oxidative stress compared to group 2.

Zinc Status of and its Association to Cardiovascular Risk Biomarkers

Mailing Address: Camila Maria Simplicio Revoredo Rua Alcides Freitas, 2066, Apt. 01. Postal Code: 64002-480, Marquês. Teresina, PI – Brazil E-mail: camilarevoredo@ufpi.edu.br; camilarevoredo@yahoo.com.br Zinc Status of and its Association to Cardiovascular Risk Biomarkers Camila Maria Simplicio Revoredo1, Heila Dias de Sousa Pinho Aguiar1, Sueli Maria Teixeira Lima1, Elise Sousa Saffnauer1, Kaluce Gonçalves de Sousa Almondes2, Aldenora Oliveira do Nascimento Holanda1, Camila Guedes Borges de Araújo1, Nadir do Nascimento Nogueira1, Dilina do Nascimento Marreiro1 Universidade Federal do Piauí (UFPI)1, Teresina, PI; Universidade de São Paulo2, São Paulo, SP – Brazil