Association between oxidative stress, inflammation and systemic manifestations in smokers and patients with mild and moderate COPD

Abstract

Evidence in the literature show that oxidative stress and systemic inflammation occur in smokers and in patients with mild/moderate chronic obstructive pulmonary disease (COPD). Comorbidities, malnutrition, decreased lean body mass, muscle dysfunction are prevalent and have adverse consequences on functional exercise capacity, general health and prognosis of patients with COPD. However, few studies have evaluated the association between oxidative stress markers, such as advanced glycation end product (AGE) and receptor advanced glycation end products (RAGE) and the influence of binding AGE / RAGE on the development of inflammatory activity in smokers and in mild/moderate COPD patients. Objectives: To evaluate the association between oxidative stress and inflammatory state. Moreover, to evaluate the relationship between muscle strength, muscle mass, systemic, functional exercise capacity, general health, oxidative stress and systemic inflammation in smokers, mild/moderate COPD patients and nonsmokers controls. Individuals and Methods: 32 active smokers (mean smoking history> 10 pack / years) without COPD and 32 active smokers (mean smoking history> 10 pack / years) or former smokers with COPD (mild/moderate), from both genders, will be consecutively selected in the Pulmonology Outpatient Clinic and in the Smoking Cessation Clinic of the Botucatu Medical School University Hospital. Thirty-two nonsmokers individuals will be the control group. All individuals will undergo to medical and smoking status evaluations, laboratory, spirometry pre-and post-bronchodilator and pulse oximetry assessment. The concentration of inflammatory mediators and indicators of oxidative stress will be measured in peripheral blood. Assessments of the body composition, the peripheral muscle strength, functional capacity (walk test six minutes) and the health status, through the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Hospital Anxiety and Depression Scale (HAD) will be performed. Statistical Analysis: Analysis of variance (ANOVA) will be used to compare demographic and general characteristics (spirometry, fat-free body mass, peripheral muscle strength and functional exercise capacity) between smokers, mild/moderate COPD patients and healthy controls. Multiple regression analysis will be used to evaluate the associations between each dependent variables (peripheral muscle strength, functional exercise capacity and quality of life) and lean body mass and the systemic inflammatory state in the three study groups isolated and comparison among them. The equations will be adjusted for possible confounding variables, and collinearity will be avoided by deleting one of the variables that show correlation. The significance level is set at 5%. Will be used the statistical package "R version" 2.6.1 (Inc, Boston, MA, USA). (AU)