BACKGROUND: The human airway is believed to be acidified in asthma. In an acidic environment nitrite is converted to nitric oxide (NO). OBJECTIVE: We hypothesized that buffering airway lining fluid acid would decrease the fraction of exhaled NO (F(ENO)). METHODS: We treated 28 adult nonsmoking subjects (9 healthy control subjects, 11 subjects with mild intermittent asthma, and 8 subjects with persistent asthma) with 3 mL of 10 mmol/L phosphate buffered saline (PBS) through a nebulizer and then serially measured F(ENO) levels. Six subjects also received PBS mouthwash alone. RESULTS: F(ENO) levels decreased after buffer inhalation. The maximal decrease occurred between 15 and 30 minutes after treatment; F(ENO) levels returned to pretreatment levels by 60 minutes. The decrease was greatest in subjects with persistent asthma (-7.1 +/- 1.0 ppb); this was more than in those with either mild asthma (-2.9 +/- 0.3 ppb) or healthy control subjects (-1.7 +/- 0.3 ppb, P < .001). Levels did not decrease in subjects who used PBS mouthwash. CONCLUSION: Neutralizing airway acid decreases F(ENO) levels. The magnitude of this change is greatest in persistent asthma. These data suggest that airway pH is a determinant of F(ENO) levels downstream from NO synthase activation. CLINICAL IMPLICATIONS: Airway biochemistry modulates F(ENO) levels. For example, nitrite is converted to NO in the airway, particularly the inflamed airway, by means of acid-based chemistry. Thus airway pH should be considered in interpreting clinical F(ENO) values. In fact, PBS challenge testing integrates airway pH and F(ENO) analysis, potentially improving the utility of F(ENO) as a noninvasive test for the type and severity of asthmatic airway inflammation.
BACKGROUND: The human airway is believed to be acidified in asthma. In an acidic environment nitrite is converted to nitric oxide (NO). OBJECTIVE: We hypothesized that buffering airway lining fluid acid would decrease the fraction of exhaled NO (F(ENO)). METHODS: We treated 28 adult nonsmoking subjects (9 healthy control subjects, 11 subjects with mild intermittent asthma, and 8 subjects with persistent asthma) with 3 mL of 10 mmol/L phosphate buffered saline (PBS) through a nebulizer and then serially measured F(ENO) levels. Six subjects also received PBS mouthwash alone. RESULTS: F(ENO) levels decreased after buffer inhalation. The maximal decrease occurred between 15 and 30 minutes after treatment; F(ENO) levels returned to pretreatment levels by 60 minutes. The decrease was greatest in subjects with persistent asthma (-7.1 +/- 1.0 ppb); this was more than in those with either mild asthma (-2.9 +/- 0.3 ppb) or healthy control subjects (-1.7 +/- 0.3 ppb, P < .001). Levels did not decrease in subjects who used PBS mouthwash. CONCLUSION: Neutralizing airway acid decreases F(ENO) levels. The magnitude of this change is greatest in persistent asthma. These data suggest that airway pH is a determinant of F(ENO) levels downstream from NO synthase activation. CLINICAL IMPLICATIONS: Airway biochemistry modulates F(ENO) levels. For example, nitrite is converted to NO in the airway, particularly the inflamed airway, by means of acid-based chemistry. Thus airway pH should be considered in interpreting clinical F(ENO) values. In fact, PBS challenge testing integrates airway pH and F(ENO) analysis, potentially improving the utility of F(ENO) as a noninvasive test for the type and severity of asthmatic airway inflammation.
Authors: Nadzeya Marozkina; Jürgen Bosch; Calvin Cotton; Laura Smith; James Seckler; Khalequz Zaman; Shagufta Rehman; Ammasi Periasamy; Herbert Gaston; Ghaith Altawallbeh; Michael Davis; David R Jones; Robert Schilz; Scott H Randell; Benjamin Gaston Journal: Am J Physiol Lung Cell Mol Physiol Date: 2019-05-22 Impact factor: 5.464
Authors: W Gerald Teague; Brenda R Phillips; John V Fahy; Sally E Wenzel; Anne M Fitzpatrick; Wendy C Moore; Annette T Hastie; Eugene R Bleecker; Deborah A Meyers; Stephen P Peters; Mario Castro; Andrea M Coverstone; Leonard B Bacharier; Ngoc P Ly; Michael C Peters; Loren C Denlinger; Sima Ramratnam; Ronald L Sorkness; Benjamin M Gaston; Serpil C Erzurum; Suzy A A Comhair; Ross E Myers; Joe Zein; Mark D DeBoer; Anne-Marie Irani; Elliot Israel; Bruce Levy; Juan Carlos Cardet; Wanda Phipatanakul; Jonathan M Gaffin; Fernando Holguin; Merritt L Fajt; Shean J Aujla; David T Mauger; Nizar N Jarjour Journal: J Allergy Clin Immunol Pract Date: 2017-08-31
Authors: Anne M Fitzpatrick; Janet T Holbrook; Christine Y Wei; Meredith S Brown; Robert A Wise; W Gerald Teague Journal: J Allergy Clin Immunol Pract Date: 2014-05-21
Authors: Lei Liu; W Gerald Teague; Serpil Erzurum; Anne Fitzpatrick; Sneha Mantri; Raed A Dweik; Eugene R Bleecker; Deborah Meyers; William W Busse; William J Calhoun; Mario Castro; Kian Fan Chung; Douglas Curran-Everett; Elliot Israel; W Nizar Jarjour; Wendy Moore; Stephen P Peters; Sally Wenzel; John F Hunt; Benjamin Gaston Journal: Chest Date: 2010-10-21 Impact factor: 9.410