8-epi-prostaglandin-f2alpha and Cough

The mechanisms of cough in asthma are unclear. Asthma is associated with an oxidative stress. Many reactive oxygen species sensitize or activate sensory C-fibers which are capable to induce cough. It was hypothesized that oxidative stress in the airways might contribute to the cough severity in asthma. Exhaled breath condensate samples were collected in ten healthy and 26 asthmatic subjects. The concentration of 8-isoprostane was measured. In addition, the subjects filled in Leicester Cough Questionnaire and underwent cough provocation tests with dry air hyperpnoea and hypertonic saline, among other measurements. Among the asthmatic subjects, high 8-isoprostane was associated with severe cough response to hyperpnoea (p=0.001), low Leicester Cough Questionnaire values (indicating severe subjective cough, p=0.02), and usage of combination asthma drugs (p=0.03-0.04). However, the 8-isoprostane concentrations did not differ significantly between the healthy and the asthmatic subjects. Airway oxidative stress may be associated with experienced cough severity and measured cough sensitivity in asthma.

Topics: Adult; Asthma; Breath Tests; Bronchial Provocation Tests; Case-Control Studies; Chronic Disease; Cohort Studies; Cough; Dinoprost; Exhalation; Female; Humans; Hyperventilation; Male; Middle Aged; Oxidative Stress; Reference Values; Severity of Illness Index; Spirometry; Statistics, Nonparametric

Severe asthma is characterized by persistent airway inflammation and increased formation of reactive oxygen species.. Glutathione (GSH) is an important antioxidant in the epithelial lining fluid (ELF). We hypothesized that airway GSH homeostasis was altered in children with severe asthma and was characterized by decreased GSH and increased glutathione disulfide (GSSG) concentrations.. Bronchoalveolar lavage was obtained from 65 children with severe asthma, including 35 children with baseline airway obstruction evidenced by FEV(1) <80%. Control data were obtained from 6 children with psychogenic (habit) cough or vocal cord dysfunction undergoing diagnostic bronchoscopy and 35 healthy adult controls. GSH, GSSG, and other determinants of airway oxidative stress including glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), malondialdehyde, 8-isoprostane, and H(2)O(2) were measured in the ELF. The ELF redox potential was calculated from GSH and GSSG by using the Nernst equation.. Compared with controls, subjects with severe asthma had lower airway GSH with increased GSSG despite no differences in GST, GR, and GPx activities between groups. This was accompanied by increased malondialdehyde, 8-isoprostane, and H(2)O(2) concentrations in the ELF. GSH oxidation was most apparent in subjects with severe asthma with airway obstruction and was supported by an upward shift in the ELF GSH redox potential.. Children with severe asthma have increased biomarkers of oxidant stress in the ELF that are associated with increased formation of GSSG and a shift in the GSH redox potential toward the more oxidized state.

Topics: Adolescent; Adult; Antioxidants; Asthma; Biomarkers; Bronchoalveolar Lavage Fluid; Child; Child, Preschool; Cough; Dinoprost; Female; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Glutathione Transferase; Homeostasis; Humans; Hydrogen Peroxide; Lung; Male; Malondialdehyde; Oxidation-Reduction; Oxidative Stress; Voice Disorders