Bronchial epithelium in children: a key player in asthma

Abstract

Bronchial epithelium is a key element of the respiratory airways. It constitutes the interface between the environment and the host. It is a physical barrier with many chemical and immunological properties. The bronchial epithelium is abnormal in asthma, even in children. It represents a key component promoting airway inflammation and remodelling that can lead to chronic symptoms. In this review, we present an overview of bronchial epithelium and how to study it, with a specific focus on children. We report physical, chemical and immunological properties from ex vivo and in vitro studies. The responses to various deleterious agents, such as viruses or allergens, may lead to persistent abnormalities orchestrated by bronchial epithelial cells. As epithelium dysfunctions occur early in asthma, reprogramming the epithelium may represent an ambitious goal to induce asthma remission in children.

FIGURE 1

Bronchial epithelium obtained from a, b) healthy children and c, d) asthmatic children after a, c) Periodic acid–Schiff staining and b, d) Trichrome Masson staining.

FIGURE 2

Schematic of the differentiation protocol to generate mature airway epithelium using an air–liquid interface. Haematoxylin staining shows cilia on some cells.