Effects of naturally-occurring acid fog on inflammatory mediators in airway and pulmonary functions in asthmatic patients

Abstract

Floating fog occurs every summer in Kushiro City in Japan, and the annual average of fog water pH in the past 4 years has been under 5.0. We previously reported that epidemiologically fog was the most important positive factor contributing to increased hospital visits of asthmatic patients compared with other meteorological values and air pollutants. This study aimed to investigate the mechanism of the effects of naturally-occurring acid fog on asthmatic patients. We compared pulmonary functions and inflammatory mediators in induced sputum between the foggy (July 1995) and the non-foggy (May 1996) season, and assessed airway responsiveness to hypo-osmolar aerosol. Forty-four out of 118 asthmatic patients of Kushiro City residents participated, pulmonary function tests were completed in 36 patients, and sputum data were available in 26 patients in both seasons. Percent forced expiratory volume in 1 sec (FEV1) was significantly (P< 0.05) decreased, and % peak expiratory flow rate (PEFR) had a trend to decrease in the foggy season more than in the non-foggy, and sputum eosinophil cationic protein (ECP) and interleukin (IL)-8 were higher in the foggy season but not significantly. A moderate inverse correlation was revealed between sputum ECP and %PEFR in the foggy season (r= -0.55, P<0.005). Subjects were divided into two groups according to the best PEFR; one had >10% lower PEFR levels in the foggy season than in the non-foggy season (Group A, n = 7), the remainder did not (Group B, n = 19). In group A, sputum ECP was significantly increased (P< 0.01) in the foggy season, but there were no changes in IL-8 and prostaglandin D2. Ultrasonic nebulized distilled water provocation test revealed no differences between group A and B. These results suggested that eosinophilic inflammation rather than hypo-osmolar effect of fog might contribute to respiratory deterioration by inhalation of naturally-occurring acid fog.

Determinants of Exhaled Breath Condensate pH in a Large Population With Asthma

“…lism increases F e NO acutely in vivo but depletes airway GSNO levels long-term, decreasing F e NO; indeed, GSNO metabolism is increased in many patients with asthma. 32,33,[36][37][38][39] Single nucleotide polymorphisms in GSNO metabolic enzyme, GSNO reductase, are predictive of asthma, 38,40 and mice defi cient in GSNO reductase are protected from experimental asthma. 41 Note in this regard that GSNO reductase activity can be induced by allergen exposure and can result in increased methacholine responsiveness.…”

“…Further, decreased airway pH recapitulates many features of asthma. 1,2,7,[30][31][32][33] Airway pH appears to be normally distributed in the general population, measured at a retail outlet store, 34 though outliers with low pH might be explained if some of the subjects had unreported asthma, GER, or intercurrent infections. 11,12,16,19 Here, we report that EBC pH in a large cohort with wellcharacterized severe and nonsevere asthma is, on the whole, normal.…”

The GPCR OGR1 (GPR68) mediates diverse signalling and contraction of airway smooth muscle in response to small reductions in extracellular pH

“…Numerous recent studies have suggested alterations in airway pH contribute to the pathophysiology of obstructive airway disease (reviewed in Ricciardolo et al ., 2004). Airway acidification caused by either exogenous acids (polluted air constituting an ‘acid fog’) (Honma et al ., 2000), endogenous acids (gastroesophageal reflux with microaspiration) (Ricciardolo, 2001; Hunt and Gaston, 2008), or as a consequence of airway inflammation (Kostikas et al ., 2002; Brunetti et al ., 2008) can reduce the pH of the airway and increase airway smooth muscle (ASM) contractility and airway resistance. Two major mechanisms mediating acid‐induced bronchoconstriction have been identified.…”

Differing estrogen activities in the organic phase of air particulate matter collected during sunny and foggy weather in a Chinese city detected by a recombinant yeast bioassay

“…Clouds and fog play an important role as processors of atmospheric aerosols and soluble gases. Concerns are increasing about adverse effects of fog on respiratory function and airway response in asthmatics (Honma et al, 2000;Fontana et al, 2002). Urban air particulate material (APM) is a complex mixture of chemicals released from vehicular and industrial sources, together with oil fumes from house cooking and re-entrained particles from roads.…”