Inhaled mannitol changes the sputum properties in asthmatics with mucus hypersecretion.

Area of Science:

• Respiratory Medicine
• Pulmonary Physiology
• Pharmacology

Background:

• Asthma patients with mucus hypersecretion often experience impaired secretion clearance, leading to mucus plugs and airway obstruction.
• Inhaled mannitol has shown potential in facilitating mucus clearance.
• Chronic cough and sputum production are common symptoms in asthmatics, significantly impacting quality of life.

Purpose of the Study:

• To investigate the effects of inhaled mannitol on the physical properties of sputum in asthmatics.
• To assess changes in sputum viscosity, elasticity, surface tension, contact angle, and percentage solids.
• To determine if mannitol's osmotic effect influences sputum characteristics relevant to airway clearance.

Main Methods:

• Sputum samples were collected from 12 adult asthmatics (non-smokers) over four visits.
• Measurements included sputum viscosity, elasticity, surface tension, contact angle-glass, and percentage solids.
• Eformoterol was administered prior to mannitol inhalation (varying doses) to prevent bronchoconstriction; montelukast was used in one visit.

Main Results:

• Inhaled mannitol (360 mg) significantly reduced sputum elasticity (P < 0.0001) and viscosity (P < 0.0001).
• Mannitol also decreased surface tension (P < 0.0001), contact angle-glass (P < 0.0001), and percentage solids (P < 0.0001).
• No significant sputum property changes were observed after eformoterol alone; montelukast did not further enhance mannitol's effects.

Conclusions:

• Inhaled mannitol effectively reduces sputum viscoelasticity, surface tension, contact angle, and solids content in asthmatics with chronic cough and sputum production.
• These changes are consistent with mannitol's osmotic action, drawing water into the airway lumen and thinning secretions.
• Mannitol represents a promising therapeutic agent for improving mucus clearance in specific asthmatic populations.