Ultrastructural Alteration of Ciliated Epithelium of Bronchoalveolar Lavage Fluids

This chapter delves into the intricate realm of ciliated epithelium in bronchoalveolar lavage fluids (BALF), shedding light on the ultrastructural alterations that occur in response to various pathological conditions. Ciliated epithelial cells, a crucial component of the respiratory tract’s mucociliary apparatus, play a vital role in maintaining the airway’s integrity and function. However, in case of exposure to environmental stressors, pollutants, and infectious agents, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to a cascade of cellular and molecular events, culminating in ultrastructural changes that compromise the ciliated epithelium’s functionality. Through a combination of advanced imaging techniques, including transmission electron microscopy (TEM) and scanning electron microscopy (SEM), this chapter provides a detailed examination of the alterations in ciliary structure, beat frequency, and coordination, as well as changes in the apical junctional complex, microvilli, and cytoskeletal organization of ciliated epithelium infected with coronavirus. Furthermore, we discuss the implications of these ultrastructural alterations on mucociliary clearance, airway inflammation, and the pathogenesis of respiratory diseases, such as chronic obstructive pulmonary disease (COPD), asthma, and pneumonia. By elucidating the complex relationships between viral exposures and cellular responses leading to ultrastructural changes in ciliated epithelial cells, this chapter aims to contribute to the development of novel therapeutic strategies and diagnostic tools for respiratory diseases, ultimately promoting a better understanding of the intricate mechanisms governing airway health and disease.