Alveolar nitric oxide and asthma control in mild untreated asthma

doi:10.1016/j.jaci.2013.03.009

Journal of Allergy and Clinical Immunology

Volume 131, Issue 6, June 2013, Pages 1513-1517

https://doi.org/10.1016/j.jaci.2013.03.009 Get rights and content

Background

The role of the peripheral airways in asthma is increasingly being recognized as a potential target for the achievement of optimal control of the disease. We postulated that the inflammatory changes of the small airways are implicated in the lack of asthma control in mild asthma.

Objective

To test this hypothesis, we measured the alveolar fraction of exhaled NO (C_alvNO) in patients with mild asthma with different levels of control of symptoms.

Methods

Seventy-eight patients with asthma (35 men, age, 37 ± 15 years; FEV₁ percentage of predicted, 100% ± 9%) were studied. Asthma control was assessed by using the Asthma Control Test (ACT). Measurements of exhaled NO at multiple constant flows were performed.

Results

Bronchial NO concentrations were 27.1 ± 20 ppb, and C_alvNO levels were 5.7 ± 3.4 ppb. The ACT score was 20 ± 4.2. The level of asthma control was not associated with bronchial NO concentrations (r_s = 0.16, P = .15). However, a significant correlation was found between the ACT score and C_alvNO (r_s = 0.25, P = .03). Moreover, C_alvNO was significantly higher in patients with uncontrolled asthma than in patients with controlled/partially controlled asthma (6.7 ± 2.6 ppb vs 4.9 ± 2.6 ppb, respectively, P = .02). In the subgroup of patients with asthma who underwent extrafine inhaled corticosteroid treatment, the magnitude of the inhaled corticosteroid–induced improvement in asthma control positively correlated with baseline C_alvNO at 1 month (r_s = 0.39, P = .003) and at 3 months (r_s = 0.49, P < .0001).

Conclusions

The alveolar component of exhaled NO is associated with the lack of asthma control in patients with mild, untreated asthma. This observation supports the notion that abnormalities of the peripheral airways are implicated in the mildest forms of asthma.

Section snippets

Subjects

We aimed at recruiting 100 consecutive individuals attending the Allergy Outpatient Clinic of the Division of Respiratory Diseases of the University of Palermo (Palermo, Italy) who had received the diagnosis of asthma in accordance with the Global Initiative for Asthma guidelines.¹⁵ Patients were enrolled after consultation in our department, including the first visit during which clinical and functional assessments were performed. We aimed at selecting patients with mild asthma with FEV₁ value

Results

Out of the 100 individuals who met the inclusion criteria, 22 did not enter in the study protocol because they refused to provide the consent (3 subjects), or experienced an exacerbation in the 4 weeks preceding the study procedures (7 subjects), or did not adequately perform the study procedures (12 subjects). A total of 78 never smoker, mild asthmatic patients were enrolled in the present study. Demographic and functional characteristics of the recruited subjects are described in Table I.

Discussion

The findings of the present study demonstrate that in patients with mild, untreated asthma, the level of asthma control is associated with inflammatory changes of the peripheral airways. In addition, the alveolar NO concentrations appear to predict the response to extrafine ICS treatment in terms of asthma control. Taken together, these observations suggest that abnormalities of the peripheral airways are implicated in clinical presentations of mildest forms of asthma.

The use of markers of

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: Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest.

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Asthma and lower airway diseaseAlveolar nitric oxide and asthma control in mild untreated asthma

Background

Objective

Methods

Results

Conclusions

Section snippets

Subjects

Results

Discussion

Chest

Chest

J Allergy Clin Immunol

Ann Allergy Asthma Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

Chest

J Allergy Clin Immunol

The small airways and distal lung compartment in asthma and COPD: a time for reappraisal

Allergy

The role of small airways in monitoring the response to asthma treatment: what is beyond FEV1?

Allergy

The use of exhaled nitric oxide to guide asthma management: a randomized controlled trial

Am J Respir Crit Care Med

Exhaled nitric oxide and asthma control: a longitudinal study in unselected patients

Eur Respir J

A two-compartment model of pulmonary nitric oxide exchange dynamics

J Appl Physiol

Alveolar nitric oxide in adults with asthma: evidence of distal lung inflammation in refractory asthma

Eur Respir J

Inhaled fluticasone decreases bronchial but not alveolar nitric oxide output in asthma

Eur Respir J

Asthma and lower airway disease
Alveolar nitric oxide and asthma control in mild untreated asthma