The relationship between oxidative stress and acid stress in adult patients with mild asthma.
BACKGROUND
Oxidative stress plays an important role in the pathogenesis of asthma. Interestingly, a low airway pH and a high concentration of 8-isoprostane, a marker of oxidative stress, has been reported to cause inflammatory airway diseases. However, the relationship between these 2 markers and pulmonary function has not been determined in mild asthma patients.


METHODS
pH and 8-isoprostane concentration were measured in exhaled breath condensate (EBC) from patients with mild asthma (n = 44) and healthy subjects (n = 20). The relationship between acid stress (pH) and oxidative stress (8-isoprostane) was then analyzed, along with the relationships between these 2 markers and lung function.


RESULTS
The median (interquartile range [IQR]) pH of EBC was significantly lower in asthma patients than in control subjects (7.53 [7.41-7.68] vs 7.70 [7.62-7.74], P < .05), while the median (IQR) 8-isoprostane concentration of EBC was significantly higher in asthma patients than control subjects (16.2 [11.7-19.1] vs 3.5 [2.6-7.9] pg/mL, P < .05). There was no correlation between pH and 8-isoprostane concentration. Furthermore, lung function was not correlated with either pH or 8-isoprostane concentrations in EBC.


CONCLUSIONS
Acid stress and oxidative stress assessed by pH and 8-isoprostane concentration, respectively, in EBC did not show parallel changes associated with asthma and were not correlated with lung function in asthma patients. These 2 stress factors may have different roles in the pathogenesis of asthma.
Zhao
J J
JJ
Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan.
Shimizu
Y
Y
Dobashi
K
K
Kawata
T
T
Ono
A
A
Yanagitani
N
N
Kaira
K
K
Utsugi
M
M
Hisada
T
T
Ishizuka
T
T
Mori
M
M
D000328:Adult; D001249:Asthma / Q000378:metabolism*; D001944:Breath Tests; D015237:Dinoprost / Q000031:analogs & derivatives / Q000032:analysis; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D018384:Oxidative Stress
C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost