[The relationship between nutritional status and oxidative stress markers, pulmonary function in patients with stable chronic obstructive pulmonary disease].

Objective: To investigate the association between the nutritional status of patients with chronic obstructive pulmonary disease (COPD) and the levels of serum oxidative stress markers protein carbonyls (PC), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), total antioxidant capacity (TAC) and pulmonary function. Methods: 200 patients with stable COPD (the COPD group) and 100 healthy individuals (the control group) who visited during June 2014 and August 2014 were enrolled in our study. The levels of PC, MDA, 8-OHdG and TAC in serum were detected. Pulmonary function was tested. Nutritional status was assessed by mini nutritional assessment (MNA) that classified the nutrition class. Results: The levels of PC, MDA, and 8-OHdG in serum increased significantly in the COPD group [3.82 (1.79, 6.83) μg/L, 3.89(2.77, 5.40) μmol/L and 359.18(259.25, 587.85) ng/L, respectively], and the levels of TAC in serum decreased significantly in COPD group [11.35(4.81, 20.20)U/ml], as compared with the control group [2.29(1.08, 3.26) μg/L, 3.08(2.32, 4.03) μmol/L, 311.37(265.47, 374.08) ng/L and 18.81(15.21, 23.19) U/ml, respectively, all P<0.05]. All the nutrition assessment parameters were gradually decreased as nutritional status worsen (all P<0.05). In malnourished (risk) COPD subgroup, the levels of PC and TAC in serum increased significantly [6.10(3.02, 8.18) μg/L and 13.33(6.07, 23.96) U/ml, respectively] and the FEV(1)% and FEV(1)/FVC index decreased significantly [42.90(34.68, 71.23) and 46.96(38.96, 60.63), respectively] as compared the well-nourished COPD subgroup [3.25(1.61, 5.37) μg/L, 9.99(4.41, 16.77) U/ml, 69.10(45.95, 89.23) and 53.32(42.13, 63.15), all P<0.05]. Furthermore, we had found that the upper arm muscle circumference, calf circumference and BMI were positively correlated with MNA (r=0.498, 0.587, 0.781, P<0.001), negatively correlated with PC (r=-0.209, -0.195, -0.231, P<0.05) and positively correlated with FEV(1)% (r=0.223, 0.274, 0.350, P<0.05). The upper arm muscle circumference and BMI were positively correlated with FEV(1)/FVC (r=0.166, 0.224, P<0.05). In COPD group, the level of PC in serum and FEV(1)% were important factor in MNA score, and the impacts of FEV(1)% were greater than the level of PC(β=0.367, -0.304, P<0.001). Conclusion: The protein carbonylation and airflow limitation might be closely related to malnutrition.