The role of airway mucus in pulmonary toxicology.

Abstract

Airway mucus is a complex airway secretion whose primary function as part of the mucociliary transport mechanism is to to serve as renewable and transportable barrier against inhaled particulates and toxic agents. The rheologic properties necessary for this function are imparted by glycoproteins, or mucins. Some respiratory disease states, e.g., asthma, cystic fibrosis, and bronchitis, are characterized by quantitative and qualitative changes in mucus biosynthesis that contribute to pulmonary pathology. Similar alterations in various aspects of mucin biochemistry and biophysics, leading to mucus hypersecretion and altered mucus rheology, result from inhalation of certain air pollutants, such as ozone, sulfur dioxide, nitrogen dioxide, and cigarette smoke. The consequences of these pollutant-induced alterations in mucus biology are discussed in the context of pulmonary pathophysiology and toxicology. -Environ Health Perspect 1 02(Suppl 2): 89-103 (1994).

Nanoparticles reveal that human cervicovaginal mucus is riddled with pores larger than viruses

“…The concentration of mucins in mucus gels typically ranges between 1-5% (1,(24)(25)(26)(27)(28). Based on these values, a cubic lattice model that assumes mucins to be long rigid polymers predicts an average pore size of 40-100 nm.…”

Protein P200 Is Dispensable for Mycoplasma pneumoniae Hemadsorption but Not Gliding Motility or Colonization of Differentiated Bronchial Epithelium

“…Estimates of the thickness of the mucus layer over airway epithelium vary from 5 to 7 m to perhaps as much as 10-fold higher, while the upward flow rate toward the trachea is approximately 4.2 to 7 mm/min (6,31,34). The NHBE cell cultures used here produced approximately 1.25 l of mucus/h/cm 2 , and ciliary action swept fluorescent beads to the periphery in Transwell inserts (data not shown).…”

Cystic fibrosis mice lacking Muc1 have reduced amounts of intestinal mucus.

“…The luminal surface of the tracheobronchial, gastrointestinal (GI), 1 and reproductive tracts are lubricated and protected by the production of a thin mucus barrier. In its normal state the mucus is composed of 95% water, 2% glycoproteins, and 1% each of protein, lipids, and inorganic salts (1).…”

“…In its normal state the mucus is composed of 95% water, 2% glycoproteins, and 1% each of protein, lipids, and inorganic salts (1). The major structural components of mucus, which confer its viscoelastic properties, are glycoproteins called mucins.…”