Mucociliary tracheal transport rates in man

Area of Science:

• Pulmonary Physiology
• Nuclear Medicine Imaging

Background:

• Mucociliary clearance is vital for airway defense.
• Accurate measurement of mucociliary tracheal transport rates (MTTRs) is crucial for understanding respiratory health and disease.

Purpose of the Study:

• To describe a new method for measuring MTTRs using inhaled radiolabeled microspheres.
• To establish baseline MTTRs in healthy adults and assess variability.
• To investigate the effects of drugs and smoking on MTTRs.

Main Methods:

• Healthy adults inhaled an aerosol of 99mTc-labeled albumin microspheres.
• Microsphere deposition in large airways followed by gamma camera tracking.
• MTTRs calculated based on the transport of microsphere boli up the trachea.

Main Results:

• A log-normal distribution of MTTRs was observed in 42 healthy adults (geometric mean 3.6 mm/min).
• Individual MTTRs demonstrated low short-term variation (25%) and were stable over time.
• Atropine decreased MTTRs, while Th1165a increased them; smoking had no significant effect.

Conclusions:

• The described method provides a reliable assessment of MTTRs.
• Individual MTTRs are relatively stable, but sensitive to pharmacological agents.
• Smoking does not appear to significantly impact short-term MTTRs in healthy individuals.