Biomarcadores do estresse oxidativo e determinantes da síndrome metabólica em adultos jovens saudáveis

• Ano de defesa: 2010
• Autor(a) principal: Barbosa, Kiriaque Barra Ferreira
• Orientador(a): Bressan, Josefina
• Banca de defesa: Costa, Neuza Maria Brunoro , Oliveira, Leandro Licursi de
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Ciência e Tecnologia de Alimentos
• Departamento: Ciência de Alimentos; Tecnologia de Alimentos; Engenharia de Alimentos
• País: BR
• Palavras-chave em Português: Estresse oxidativo; Obesidade; Síndrome metabólica
• Palavras-chave em Inglês: Oxidative stress; Obesity; Metabolic syndrome
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS
• Link de acesso: http://locus.ufv.br/handle/123456789/446

Oxidative stress, assessed by its biomarkers, has been suggested as an event directly associated with metabolic syndrome. In this context, it is important to better understanding the mechanisms involved in the etiology of this association. The purpose of this study was to evaluate, in healthy young adults, the potential associations between oxidative biomarkers, oxidized low density lipoprotein (oxLDL), total antioxidant capacity of plasma (TAC), erythrocytes glutathione peroxidase activity (GPx) and several anthropometric, body composition, clinical, biochemical and dietary intake data linked with metabolic syndrome. This study evaluated 160 young healthy individuals, aged between 18 and 35. Anthropometric and body composition measurements were carried out following standardized protocols. Systolic and diastolic blood pressures were measured by a mercury sphygmomanometer. Blood samples were draw by vein puncture after a 12-hour overnight fast. All samples (plasma, serum and erythrocytes) were immediately stored at -80°C until assay. Serum glucose, total cholesterol, high-density lipoprotein cholesterol (HDL-c), triacylglycerols, uric acid and ceruloplasmin concentrations, were assessed by an automated colorimetric or turbidmetric assay, with specific commercially available kits. Plasma oxLDL and insulin concentrations were measured by an ELISA assay kit as described by the supplier. TAC was measured by a colorimetric assay kit and GPx activity by a kinetic enzimatic assay kit, as described by the supplier. Selenium, copper and zinc nail concentrations were measured by atomic absorption spectrophotometry. A 72-h food record (3 no-consecutive days) was used to collect information about daily caloric and nutrient intake. The Kolmogorov-Smirnov normality test was used to determine variable distribution. Accordingly, the parametric Student t test or nonparametric Mann-Whitney U test was performed to detect differences between groups categorized by the median of oxidative stress biomarkers. The Spearman correlation coefficients were used to screen the statistical associations between oxidative biomarkers and interest variables. Linear regression model was fitted to identify the predictors of oxidative biomarkers. The odds ratio was determined considering the first quartile of oxLDL distribution as reference. Results are presented as mean ± SD (standard deviation). Confidence intervals (95% CIs) were used to describe linear regression coefficient &#946;) and logistic regression odds ratio (OR) values, P < 0.05 was considered statistically significant. Statistical analyses were performed by using SAS system version 8.0 for Windows. Linear regression analysis showed, total cholesterol, triacylglicerol, total cholesterol-to-HDL-c ratio,uric acid and GPx activity were positive predictors of oxLDL circulating levels. OxLDL concentration was negatively predicted by nail selenium concentration. Subjects who are in the highest quartile of circulating oxLDL (&#8805; 91.81 U/L) had increased chance of 240% (OR = 3.40; IC 95% = 1.15 to 9.96; P = 0.03) for present high levels of triacylglycerol when compared with those in the lowest quartile (< 52.62 U/L). Moreover, subjects with high circulating levels of oxLDL (> 69.36 U/L) demonstrated high values of body mass index. In addition, the following statistical correlations with oxLDL concentrations were detected: trunk fat (r = 0.16; P = 0.043), cholesterol intake (r = 0.17; P = 0.045), serum triacylglicerol (r = 0.13; P = 0.013), systolic blood pressure (r = 0.17; P = 0.027) and nail copper concentrations (r = -0.17; P = 0.046). Linear regression analysis showed that daily caloric (kcal/kg of body weight) and carbohydrate (g/kg of body weight) intake exerted negative predictive effect on TAC values. In individuals who presented a higher TAC (> 1.60 mM), the serum LDL-c, cholesterol-to-HDL-c ratio and nail selenium concentrations were significantly higher. By linear regression analysis, the GPx activity was positively predicted by oxidative conditions suchs as trunk fat and circulating levels of oxLDL. Subjects with high GPx activity (> 522.63 nmol/[ml/min]) demonstrated high values of age, daily intake of vitamin C and and moreover, low nail selenium and copper concentrations. Oxidative biomarkers such as oxLDL, TAC of plasma and erythrocytes GPx activity were related with several anthropometric, body composition, clinical, biochemical and dietary intake measurements linked to metabolic syndrome. This findings support a relevant role of these biomarkers as remarkable tools in assessing the impact of oxidative damage on the development of metabolic syndrome.