Mucociliarse

Mucociliarse, also known as mucociliary clearance, is the defense mechanism of the respiratory tract that traps inhaled particles and microorganisms in mucus and transports them out of the airways by the coordinated beating of motile cilia.

Anatomy and mechanism: The airway epithelium includes goblet cells that produce mucus and ciliated cells that propel it. The surface liquid consists of a mucus layer atop a periciliary liquid layer. Cilia beat in a coordinated, metachronal pattern toward the pharynx, moving mucus and entrapped particles out of the lungs. Adequate hydration and ionic balance of the airway surface liquid are essential for effective clearance.

Mucus composition: Mucus contains mucins, predominantly MUC5AC and MUC5B, as well as water, salts, and antimicrobial factors. This gel traps inhaled debris and pathogens while allowing ciliary transport. The mucus layer’s rheology—its thickness and viscosity—affects clearance efficiency.

Regulation and influences: The system is sensitive to environmental conditions and health status. Humidity, temperature, air quality, and hydration support clearance, while smoking, dehydration, and pollutants impair ciliary function or mucus properties. Certain diseases alter mucus production or ciliary motion, reducing transport efficiency.

Clinical relevance: Impaired mucociliary clearance contributes to chronic respiratory infections and inflammation. It is a central feature of conditions such as primary ciliary dyskinesia, cystic fibrosis, chronic rhinosinusitis, and bronchiectasis. Smoking-related ciliary dysfunction and acute infections can transiently disrupt clearance.

Assessment and management: Diagnostic approaches include evaluation of ciliary function through high-speed video microscopy, electron microscopy, and genetic testing, and measurement of nasal nitric oxide for suspected primary ciliary dyskinesia. Management emphasizes hydration and airway clearance techniques (saline irrigation, chest physiotherapy), avoidance of irritants, and treatment of underlying diseases; mucolytics and hypertonic saline may be used to enhance clearance.