[Nitric oxide and the upper airways: recent discoveries]

Area of Science:

• Biochemistry
• Physiology
• Immunology

Context:

• Nitric oxide (NO) is synthesized from L-arginine via nitric oxide synthase (NOS) in human tissues.
• NO functions as a crucial signaling molecule in the cardiovascular system, regulating vascular tone.
• Exhaled NO, primarily produced in the nose and sinuses, plays vital roles in upper airway defense and lung function.

Purpose:

• To review the origin, metabolism, and functions of nitric oxide (NO) in the upper airways.
• To discuss the techniques and implications of measuring nasal NO.
• To highlight NO's role as a biomarker for sinonasal inflammation.

Summary:

• NO is produced from L-arginine by NOS in mammalian tissues.
• In the upper airways, NO enhances ciliary function and provides antimicrobial defense.
• NO is implicated in lung ventilation/perfusion matching and serves as an inflammatory marker in sinonasal diseases.

Impact:

• Understanding NO's role in the upper airways can lead to improved diagnostics for sinonasal conditions.
• Nasal NO measurement offers a non-invasive method for assessing airway inflammation.
• This review consolidates knowledge on NO's multifaceted functions in respiratory health.