Regulation of mucociliary clearance in health and disease

Abstract

Airway secretions are cleared by mucociliary clearance (MCC), in addition to other mechanisms such as cough, peristalsis, two‐phase gas–liquid flow and alveolar clearance. MCC comprises the cephalad movement of mucus caused by the cilia lining the conducting airways until it can be swallowed or expectorated. MCC is a very complex process in which many variables are involved, all of which may modify the final outcome. The structure, number, movement and co‐ordination of the cilia present in the airways as well as the amount, composition and rheological properties of the periciliary and mucus layers are determinants of MCC. Physiological factors such as age, sex, posture, sleep and exercise are reported to influence MCC due to a change in the cilia, the mucus or the periciliary layer, or a combination of these. Environmental pollution is suspected to have a depressant effect on MCC dependent on different factors such as pollutant concentration and the duration of exposure. Most studies focus on sulphur dioxide, sulphuric acid, nitrogen dioxide and ozone. Tobacco smoke and hairspray have been noted to have a negative influence on MCC. Some diseases are known to affect MCC, mostly negatively. The underlying mechanism differs from one illness to another. Immotile cilia syndrome, asthma, bronchiectasis, chronic bronchitis, cystic fibrosis and some acute respiratory tract infections are among the most frequently reported. The present paper reviews normal mucociliary clearance and the effects of diseases on this process.

The Effect of Ageing on Nasal Mucociliary Clearance in Women: A Pilot Study

“…This could be the result of abnormal ciliary ultrastructure or occur de novo [3,10]. Additionally, quantitative and qualitative changes in respiratory mucus and a lower tracheal mucus velocity could be causes of impaired mucociliary clearance among the elderly [10].…”

“…Nasal mucociliary clearance (NMC) is a primary innate defence mechanism of the nose and paranasal sinuses whereby mucus secreted into the upper airways (by the goblet cells of the respiratory epithelium) traps inhaled particulate matter, allergens, and pathogens [2] and is then transported with the trapped matter (by the ciliated cells of the respiratory epithelium which beat at a frequency of 12 to 15 Hz) [3] to the pharynx, where it is swallowed [4]. NMC is the mirror image of bronchial mucociliary clearance [5] and the ciliary beat frequency of nasal mucosa correlates with that of tracheal mucosa [6,7].…”

Mild dehydration: a risk factor of broncho-pulmonary disorders?

“…There is ample information on regulation of MC in health and disease (Houtmeyers et al, 1999); moreover, new models describe the regulation of volume and composition of airway surface fluid more precisely (Wang et al, 2001). However, there is only spare information about a possible effect of local or systemic hydration on MC.…”

Dinámica y patología del barrido mucociliar como mecanismo defensivo del pulmón y alternativas farmacológicas de tratamiento

“…Estas alteraciones pueden perpetuarse por la acción de mediadores de inflamación 29,30 . La eficacia del barrido mucociliar disminuye especialmente durante exacerbaciones de la enfermedad 31,32 .…”

“…También se ha descrito hipertrofia de glándulas submucosas que podrían hipersecretar o cambiar las caracterís-ticas reológicas del moco, generando secreciones de gran viscosidad difíciles de remover, y que pueden obstruir la vía aérea 31,32 . Esta acumulación de moco es característica del asma fatal 27,33 .…”