Relationship between severity of adult community-acquired pneumonia and impairment of the antioxidant defense system

Abstract

Oxidant/antioxidant imbalance has been reported in some infectious diseases, including community-acquired pneumonia (CAP). The aim was to assess the antioxidant status in adults with CAP and its relationship with clinical severity at admission. Fifty-nine patients with CAP were enrolled and categorized at admission by the FINE score, from July 2010 to October 2012. In the same period 61 controls were enrolled. Plasma samples were obtained at admission for determination of the ferric reducing ability of plasma (FRAP) and lipid peroxidation (8-isoprostane). Erythrocyte reduced (GSH)/oxidized (GSSG) glutathione, malondialdehyde (MDA) and antioxidant enzyme activity were assessed. Antioxidant status in adults with CAP represented by FRAP and the GSH/GSSG ratio were 16.8% (p=0.03) and 39.7% (p=0.04) lower than control values, respectively. In addition, FRAP values showed a positive correlation with GSH/GSSG ratio (r=0.852; p<0.02; n=59). The CAP group showed greater lipid peroxidation in both plasma and erythrocytes. The FINE score correlated negatively with FRAP (r= -0.718; p<0.05; n=59) and positively with MDA and F2 isoprostane levels (r=0.673; p<0.05; n=59; r=0.892; p<0.01; n=59, respectively). Antioxidant status alterations correlated with clinical severity. The FRAP assay and lipid peroxidation biomarkers may provide a useful parameter for estimating the severity and the clinical outcome of patients with CAP.

Evaluation of dynamic thiol/disulfide redox state in community-acquired pneumonia

“…Muravlyova et al18 found that malondialdehyde and reactive carbonyl derivatives were significantly lower in CAP patients than in controls. Castillo et al14 showed that the antioxidant capacity of plasma, as well as glutathione and glutathione disulfide levels, were lower than in controls. In this study, we found that the total and native thiol pools were lower in patients with CAP compared with healthy controls.…”

“…Many diseases are associated with oxidative stress, including malignancies, cardiovascular disease, and neurodegenerative disease 12. A standard approach for evaluating the response of biological systems to oxidative stress involves measuring the increase or decrease of a redox-sensitive molecule 14. There are few studies in the literature regarding the oxidant/antioxidant ratio in CAP.…”

“…In the normal lung, there is a balance between antioxidants and oxidants in the airway lining fluid and extracellular spaces, which helps to maintain normal physiological functions 20. In respiratory tract infections, an influx and activation of phagocytes into the lower airways, protecting against invading microorganisms, has been observed 14,21. Polymorphonuclear leukocytes and macrophages eliminate these microorganisms via reactive oxygen species (ROS) and lysosomal enzymes.…”

“…Polymorphonuclear leukocytes and macrophages eliminate these microorganisms via reactive oxygen species (ROS) and lysosomal enzymes. An increased systemic ROS concentration may be seen in respiratory tract infections 14. Reactive oxygen species released from PMNLs and macrophages cause tissue damage in respiratory tract infections 21.…”

Biomarkers in Community-Acquired Pneumonia Assessment

“…Lower levels of GSH in CAP patients have been observed also in other studies (Kelly, 1999;Rahman and MacNee, 2000;Castillo R. et al, 2013) and suggest that deficit of GSH might predispose to pulmonary inflammation. The protective role of GSH in regard to the lower respiratory tract has been suggested; hence, use of GSH inhalations might be beneficial for cystic fibrosis treatment (Prousky, 2008;Day, 2005).…”