BACKGROUND: Cigarette smoke, with its rich content of oxidants, exacerbates the oxidative stress in asthma, contributing to lung tissue damage and to worsening of symptoms. The aim of the study was to investigate the impact of smoking on oxidative stress in patients with asthma.
METHODS: Seventy-three patients were included in the study, comprising 50 with asthma and 23 without asthma (control group). Patients with asthma were divided into three subgroups based on smoking status: no-smokers, ex-smokers, and current smokers. Various biochemical parameters (including CRP - C-reactive protein, uric acid, glucose) and complete blood count (CBC) were evaluated, focusing on oxidative stress markers such as reduced glutathione (GSH), oxidized glutathione (GSSG), malondialdehyde (MDA), and the GSH/GSSG ratio.
RESULTS: Descriptive statistics revealed low serum uric acid values in smokers (5.29 mg/dL) and ex-smokers (4.75 mg/dL) compared to the no-smokers group (5.76 mg/dL). Reduced glutathione (GSH) concentrations in the blood showed low values for ex-smokers (232.90 µmol/L) and no-smokers (249.77 µmol/L). The GSH/GSSG ratio was lower in ex-smokers (3.94) and no-smokers (5.45) compared to smokers (7.79). Statistical analysis showed a significant difference (p < 0.005) based on white blood cell count values. Malondialdehyde concentrations were measured at 2.30 mmol/L for no-smokers and at 2.45 mmol/L and 2.70 mmol/L for smokers and ex-smokers, respectively. Spearman correlations indicated significant associations between MDA and GSH (r=0.39, p<0.05), neutrophils and the GSH/GSSG ratio (r=0.40, p<0.05), and CRP and the GSH/GSSG ratio (r=0.35, p<0.05).
CONCLUSIONS: The decrease in GSH levels and the alteration of the GSH/GSSG ratio indicate a depletion of the antioxidant system and a disturbance of redox balance. The increase in MDA levels confirms the presence of oxidative damage. Exposure to cigarette smoke significantly contributes to increased oxidative stress in asthma, aggravating the disease.