Related Experiment Videos
Age-related changes in bronchial hyperreactivity to methacholine in asthmatic children
H Mochizuki1, M Shigeta, M Kato
1Department of Pediatrics, Gunma University School of Medicine, Maebashi, Japan.
Insights
Childhood bronchial hyperreactivity (BHR) changes with age, initially decreasing then increasing in asthmatic children and controls. This study tracked bronchial reactivity to methacholine (BRm) in children aged 2-13 years.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Bronchial hyperreactivity (BHR) is a hallmark of asthma.
- Understanding age-related changes in BHR is crucial for childhood respiratory health management.
Purpose of the Study:
- To investigate the influence of aging on bronchial hyperreactivity (BHR) in children.
- To characterize age-related changes in bronchial reactivity to methacholine (BRm) from 2 to 13 years of age.
Main Methods:
- Methacholine inhalation challenge with transcutaneous oxygen pressure (tcPO2) monitoring to determine the dose-response curve (Dmin-PO2).
- Respiratory resistance (Rr) measurement using oscillation technique for subjects over 6 years old (Dmin-Rr).
- Inclusion of 339 asthmatic children and 107 age-matched controls.
Main Results:
- In asthmatic children (2-7 years), Dmin-PO2 significantly decreased, then increased after age 8.
- Dmin-Rr in children aged 6-13 years showed a similar age-related increase.
- These age-related patterns in BRm were also observed in control subjects.
Conclusions:
- Bronchial reactivity to methacholine (BRm) exhibits distinct age-related changes during childhood.
- The findings suggest a dynamic interplay between aging and airway responsiveness in children, applicable to both asthmatic and healthy individuals.
Abstract:
To evaluate the influence of aging on bronchial hyperreactivity (BHR) during the childhood period, age-related changes in bronchial reactivity to methacholine (BRm) in children from 2 to 13 yr of age were studied using the same method, employing a methacholine inhalation challenge with transcutaneous oxygen pressure (tcPO2) monitoring. Three hundred and thirty-nine asthmatic subjects (male:female = 200:139, aged [mean +/- SEM] 7.2 +/- 0.2 yr) and 107 age-matched controls (male:female = 55:52, aged 5.3 +/- 0.3 yr) were enrolled in this study. TcPO2 was measured by a tcPO2 monitor, and subsequent doses of methacholine were then doubled until a 10% decrease in tcPO2 from its baseline value was reached. The cumulative dose of methacholine at the inflection point of tcPO2 (Dmin-PO2) was considered to represent the BRm. For the sake of comparison, respiratory resistance (Rr) in subjects more than 6 yr old was measured by the oscillation technique during methacholine inhalation challenge, and the threshold point of Rr (Dmin-Rr) was also considered to represent the BRm. In the asthmatic children aged 2 to 7 yr, Dmin-PO2 decreased significantly from 12.2 +/- 2.1 to 3.1 +/- 0.8 units, but after age 8 yr the values gradually increased from 3.1 +/- 0.7 to 6.4 +/- 1.6 units. In children aged 6 to 13 yr, Dmin-Rr showed the same increase as Dmin-PO2, from 2.0 +/- 0.5 to 5.8 +/- 1.4 units. These age-related changes in BRm reflected in both Dmin-PO2 and Dmin-Rr were also seen in the age-matched controls.(ABSTRACT TRUNCATED AT 250 WORDS)